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1 files changed, 2290 insertions, 0 deletions

diff --git a/llama.cpp/tests/test-jinja.cpp b/llama.cpp/tests/test-jinja.cpp
new file mode 100644
index 0000000..1f25c6a
--- /dev/null
+++ b/llama.cpp/tests/test-jinja.cpp
@@ -0,0 +1,2290 @@
+#include <string>
+#include <iostream>
+#include <random>
+#include <cstdlib>
+
+#include <nlohmann/json.hpp>
+#include <sheredom/subprocess.h>
+
+#include "jinja/runtime.h"
+#include "jinja/parser.h"
+#include "jinja/lexer.h"
+#include "jinja/utils.h"
+
+#include "testing.h"
+
+using json = nlohmann::ordered_json;
+
+static void test_template(testing & t, const std::string & name, const std::string & tmpl, const json & vars, const std::string & expect);
+
+static void test_whitespace_control(testing & t);
+static void test_conditionals(testing & t);
+static void test_loops(testing & t);
+static void test_expressions(testing & t);
+static void test_set_statement(testing & t);
+static void test_filters(testing & t);
+static void test_literals(testing & t);
+static void test_comments(testing & t);
+static void test_macros(testing & t);
+static void test_namespace(testing & t);
+static void test_tests(testing & t);
+static void test_string_methods(testing & t);
+static void test_array_methods(testing & t);
+static void test_object_methods(testing & t);
+static void test_hasher(testing & t);
+static void test_fuzzing(testing & t);
+
+static bool g_python_mode = false;
+
+int main(int argc, char *argv[]) {
+    testing t(std::cout);
+    t.verbose = true;
+
+    // usage: test-jinja [-py] [filter_regex]
+    //  -py : enable python mode (use python jinja2 for rendering expected output)
+    //        only use this for cross-checking, not for correctness
+    //        note: the implementation of this flag is basic, only intented to be used by maintainers
+
+    for (int i = 1; i < argc; i++) {
+        std::string arg = argv[i];
+        if (arg == "-py") {
+            g_python_mode = true;
+        } else {
+            t.set_filter(arg);
+        }
+    }
+
+    t.test("whitespace control", test_whitespace_control);
+    t.test("conditionals", test_conditionals);
+    t.test("loops", test_loops);
+    t.test("expressions", test_expressions);
+    t.test("set statement", test_set_statement);
+    t.test("filters", test_filters);
+    t.test("literals", test_literals);
+    t.test("comments", test_comments);
+    t.test("macros", test_macros);
+    t.test("namespace", test_namespace);
+    t.test("tests", test_tests);
+    t.test("string methods", test_string_methods);
+    t.test("array methods", test_array_methods);
+    t.test("object methods", test_object_methods);
+    if (!g_python_mode) {
+        t.test("hasher", test_hasher);
+        t.test("fuzzing", test_fuzzing);
+    }
+
+    return t.summary();
+}
+
+static void test_whitespace_control(testing & t) {
+    test_template(t, "trim_blocks removes newline after tag",
+        "{% if true %}\n"
+        "hello\n"
+        "{% endif %}\n",
+        json::object(),
+        "hello\n"
+    );
+
+    test_template(t, "lstrip_blocks removes leading whitespace",
+        "    {% if true %}\n"
+        "    hello\n"
+        "    {% endif %}\n",
+        json::object(),
+        "    hello\n"
+    );
+
+    test_template(t, "for loop with trim_blocks",
+        "{% for i in items %}\n"
+        "{{ i }}\n"
+        "{% endfor %}\n",
+        {{"items", json::array({1, 2, 3})}},
+        "1\n2\n3\n"
+    );
+
+    test_template(t, "explicit strip both",
+        "  {%- if true -%}  \n"
+        "hello\n"
+        "  {%- endif -%}  \n",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "expression whitespace control",
+        "  {{- 'hello' -}}  \n",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "inline block no newline",
+        "{% if true %}yes{% endif %}",
+        json::object(),
+        "yes"
+    );
+}
+
+static void test_conditionals(testing & t) {
+    test_template(t, "if true",
+        "{% if cond %}yes{% endif %}",
+        {{"cond", true}},
+        "yes"
+    );
+
+    test_template(t, "if false",
+        "{% if cond %}yes{% endif %}",
+        {{"cond", false}},
+        ""
+    );
+
+    test_template(t, "if else",
+        "{% if cond %}yes{% else %}no{% endif %}",
+        {{"cond", false}},
+        "no"
+    );
+
+    test_template(t, "if elif else",
+        "{% if a %}A{% elif b %}B{% else %}C{% endif %}",
+        {{"a", false}, {"b", true}},
+        "B"
+    );
+
+    test_template(t, "nested if",
+        "{% if outer %}{% if inner %}both{% endif %}{% endif %}",
+        {{"outer", true}, {"inner", true}},
+        "both"
+    );
+
+    test_template(t, "comparison operators",
+        "{% if x > 5 %}big{% endif %}",
+        {{"x", 10}},
+        "big"
+    );
+
+    test_template(t, "object comparison",
+        "{% if {0: 1, none: 2, 1.0: 3, '0': 4, true: 5} == {false: 1, none: 2, 1: 5, '0': 4} %}equal{% endif %}",
+        json::object(),
+        "equal"
+    );
+
+    test_template(t, "array comparison",
+        "{% if [0, 1.0, false] == [false, 1, 0.0] %}equal{% endif %}",
+        json::object(),
+        "equal"
+    );
+
+    test_template(t, "logical and",
+        "{% if a and b %}both{% endif %}",
+        {{"a", true}, {"b", true}},
+        "both"
+    );
+
+    test_template(t, "logical or",
+        "{% if a or b %}either{% endif %}",
+        {{"a", false}, {"b", true}},
+        "either"
+    );
+
+    test_template(t, "logical not",
+        "{% if not a %}negated{% endif %}",
+        {{"a", false}},
+        "negated"
+    );
+
+    test_template(t, "in operator (element in array)",
+        "{% if 'x' in items %}found{% endif %}",
+        {{"items", json::array({"x", "y"})}},
+        "found"
+    );
+
+    test_template(t, "in operator (substring)",
+        "{% if 'bc' in 'abcd' %}found{% endif %}",
+        json::object(),
+        "found"
+    );
+
+    test_template(t, "in operator (object key)",
+        "{% if 'key' in obj %}found{% endif %}",
+        {{"obj", {{"key", 1}, {"other", 2}}}},
+        "found"
+    );
+
+    test_template(t, "is defined",
+        "{% if x is defined %}yes{% else %}no{% endif %}",
+        {{"x", 1}},
+        "yes"
+    );
+
+    test_template(t, "is not defined",
+        "{% if y is not defined %}yes{% else %}no{% endif %}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is undefined falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is undefined attribute falsy",
+        "{{ 'yes' if not y.x else 'no' }}",
+        {{"y", true}},
+        "yes"
+    );
+
+    test_template(t, "is undefined key falsy",
+        "{{ 'yes' if not y['x'] else 'no' }}",
+        {{"y", {{}}}},
+        "yes"
+    );
+
+    test_template(t, "is empty array falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", json::array()}},
+        "yes"
+    );
+
+    test_template(t, "is empty object falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", json::object()}},
+        "yes"
+    );
+
+    test_template(t, "is empty string falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", ""}},
+        "yes"
+    );
+
+    test_template(t, "is 0 falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", 0}},
+        "yes"
+    );
+
+    test_template(t, "is 0.0 falsy",
+        "{{ 'yes' if not y else 'no' }}",
+        {{"y", 0.0}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty array truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", json::array({""})}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty object truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", {"x", false}}},
+        "yes"
+    );
+
+    test_template(t, "is non-empty string truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", "0"}},
+        "yes"
+    );
+
+    test_template(t, "is 1 truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", 1}},
+        "yes"
+    );
+
+    test_template(t, "is 1.0 truthy",
+        "{{ 'yes' if y else 'no' }}",
+        {{"y", 1.0}},
+        "yes"
+    );
+}
+
+static void test_loops(testing & t) {
+    test_template(t, "simple for",
+        "{% for i in items %}{{ i }}{% endfor %}",
+        {{"items", json::array({1, 2, 3})}},
+        "123"
+    );
+
+    test_template(t, "loop.index",
+        "{% for i in items %}{{ loop.index }}{% endfor %}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "123"
+    );
+
+    test_template(t, "loop.index0",
+        "{% for i in items %}{{ loop.index0 }}{% endfor %}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "012"
+    );
+
+    test_template(t, "loop.first and loop.last",
+        "{% for i in items %}{% if loop.first %}[{% endif %}{{ i }}{% if loop.last %}]{% endif %}{% endfor %}",
+        {{"items", json::array({1, 2, 3})}},
+        "[123]"
+    );
+
+    test_template(t, "loop.length",
+        "{% for i in items %}{{ loop.length }}{% endfor %}",
+        {{"items", json::array({"a", "b"})}},
+        "22"
+    );
+
+    test_template(t, "for over dict items",
+        "{% for k, v in data.items() %}{{ k }}={{ v }} {% endfor %}",
+        {{"data", {{"x", 1}, {"y", 2}}}},
+        "x=1 y=2 "
+    );
+
+    test_template(t, "for else empty",
+        "{% for i in items %}{{ i }}{% else %}empty{% endfor %}",
+        {{"items", json::array()}},
+        "empty"
+    );
+
+    test_template(t, "for undefined empty",
+        "{% for i in items %}{{ i }}{% else %}empty{% endfor %}",
+        json::object(),
+        "empty"
+    );
+
+    test_template(t, "nested for",
+        "{% for i in a %}{% for j in b %}{{ i }}{{ j }}{% endfor %}{% endfor %}",
+        {{"a", json::array({1, 2})}, {"b", json::array({"x", "y"})}},
+        "1x1y2x2y"
+    );
+
+    test_template(t, "for with range",
+        "{% for i in range(3) %}{{ i }}{% endfor %}",
+        json::object(),
+        "012"
+    );
+}
+
+static void test_expressions(testing & t) {
+    test_template(t, "simple variable",
+        "{{ x }}",
+        {{"x", 42}},
+        "42"
+    );
+
+    test_template(t, "dot notation",
+        "{{ user.name }}",
+        {{"user", {{"name", "Bob"}}}},
+        "Bob"
+    );
+
+    test_template(t, "negative float (not dot notation)",
+        "{{ -1.0 }}",
+        json::object(),
+        "-1.0"
+    );
+
+    test_template(t, "bracket notation",
+        "{{ user['name'] }}",
+        {{"user", {{"name", "Bob"}}}},
+        "Bob"
+    );
+
+    test_template(t, "array access",
+        "{{ items[1] }}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "b"
+    );
+
+    test_template(t, "array negative access",
+        "{{ items[-1] }}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "c"
+    );
+
+    test_template(t, "array slice",
+        "{{ items[1:-1]|string }}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "['b']"
+    );
+
+    test_template(t, "array slice step",
+        "{{ items[::2]|string }}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "['a', 'c']"
+    );
+
+    test_template(t, "tuple slice",
+        "{{ ('a', 'b', 'c')[::-1]|string }}",
+        json::object(),
+        "('c', 'b', 'a')"
+    );
+
+    test_template(t, "arithmetic",
+        "{{ (a + b) * c }}",
+        {{"a", 2}, {"b", 3}, {"c", 4}},
+        "20"
+    );
+
+    test_template(t, "string concat ~",
+        "{{ 'hello' ~ ' ' ~ 'world' }}",
+        json::object(),
+        "hello world"
+    );
+
+    test_template(t, "ternary",
+        "{{ 'yes' if cond else 'no' }}",
+        {{"cond", true}},
+        "yes"
+    );
+}
+
+static void test_set_statement(testing & t) {
+    test_template(t, "simple set",
+        "{% set x = 5 %}{{ x }}",
+        json::object(),
+        "5"
+    );
+
+    test_template(t, "set with expression",
+        "{% set x = a + b %}{{ x }}",
+        {{"a", 10}, {"b", 20}},
+        "30"
+    );
+
+    test_template(t, "set list",
+        "{% set items = [1, 2, 3] %}{{ items|length }}",
+        json::object(),
+        "3"
+    );
+
+    test_template(t, "set dict",
+        "{% set d = {'a': 1} %}{{ d.a }}",
+        json::object(),
+        "1"
+    );
+
+    test_template(t, "set dict with mixed type keys",
+        "{% set d = {0: 1, none: 2, 1.0: 3, '0': 4, (0, 0): 5, false: 6, 1: 7} %}{{ d[(0, 0)] + d[0] + d[none] + d['0'] + d[false] + d[1.0] + d[1] }}",
+        json::object(),
+        "37"
+    );
+
+    test_template(t, "print dict with mixed type keys",
+        "{% set d = {0: 1, none: 2, 1.0: 3, '0': 4, (0, 0): 5, true: 6} %}{{ d|string }}",
+        json::object(),
+        "{0: 1, None: 2, 1.0: 6, '0': 4, (0, 0): 5}"
+    );
+
+    test_template(t, "print array with mixed types",
+        "{% set d = [0, none, 1.0, '0', true, (0, 0)] %}{{ d|string }}",
+        json::object(),
+        "[0, None, 1.0, '0', True, (0, 0)]"
+    );
+
+    test_template(t, "object member assignment with mixed key types",
+        "{% set d = namespace() %}{% set d.a = 123 %}{{ d['a'] == 123 }}",
+        json::object(),
+        "True"
+    );
+
+    test_template(t, "tuple unpacking",
+        "{% set t = (1, 2, 3) %}{% set a, b, c = t %}{{ a + b + c }}",
+        json::object(),
+        "6"
+    );
+}
+
+static void test_filters(testing & t) {
+    test_template(t, "upper",
+        "{{ 'hello'|upper }}",
+        json::object(),
+        "HELLO"
+    );
+
+    test_template(t, "lower",
+        "{{ 'HELLO'|lower }}",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "capitalize",
+        "{{ 'heLlo World'|capitalize }}",
+        json::object(),
+        "Hello world"
+    );
+
+    test_template(t, "title",
+        "{{ 'hello world'|title }}",
+        json::object(),
+        "Hello World"
+    );
+
+    test_template(t, "trim",
+        "{{ '  \r\n\thello\t\n\r  '|trim }}",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "trim chars",
+        "{{ 'xyxhelloxyx'|trim('xy') }}",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "length string",
+        "{{ 'hello'|length }}",
+        json::object(),
+        "5"
+    );
+
+    test_template(t, "replace",
+        "{{ 'hello world'|replace('world', 'jinja') }}",
+        json::object(),
+        "hello jinja"
+    );
+
+    test_template(t, "length list",
+        "{{ items|length }}",
+        {{"items", json::array({1, 2, 3})}},
+        "3"
+    );
+
+    test_template(t, "first",
+        "{{ items|first }}",
+        {{"items", json::array({10, 20, 30})}},
+        "10"
+    );
+
+    test_template(t, "last",
+        "{{ items|last }}",
+        {{"items", json::array({10, 20, 30})}},
+        "30"
+    );
+
+    test_template(t, "reverse",
+        "{% for i in items|reverse %}{{ i }}{% endfor %}",
+        {{"items", json::array({1, 2, 3})}},
+        "321"
+    );
+
+    test_template(t, "sort",
+        "{% for i in items|sort %}{{ i }}{% endfor %}",
+        {{"items", json::array({3, 1, 2})}},
+        "123"
+    );
+
+    test_template(t, "sort reverse",
+        "{% for i in items|sort(true) %}{{ i }}{% endfor %}",
+        {{"items", json::array({3, 1, 2})}},
+        "321"
+    );
+
+    test_template(t, "sort with attribute",
+        "{{ items|sort(attribute='name')|join(attribute='age') }}",
+        {{"items", json::array({
+            json({{"name", "c"}, {"age", 3}}),
+            json({{"name", "a"}, {"age", 1}}),
+            json({{"name", "b"}, {"age", 2}}),
+        })}},
+        "123"
+    );
+
+    test_template(t, "sort with numeric attribute",
+        "{{ items|sort(attribute=0)|join(attribute=1) }}",
+        {{"items", json::array({
+            json::array({3, "z"}),
+            json::array({1, "x"}),
+            json::array({2, "y"}),
+        })}},
+        "xyz"
+    );
+
+    test_template(t, "join",
+        "{{ items|join(', ') }}",
+        {{"items", json::array({"a", "b", "c"})}},
+        "a, b, c"
+    );
+
+    test_template(t, "join default separator",
+        "{{ items|join }}",
+        {{"items", json::array({"x", "y", "z"})}},
+        "xyz"
+    );
+
+    test_template(t, "abs",
+        "{{ -5|abs }}",
+        json::object(),
+        "5"
+    );
+
+    test_template(t, "int from string",
+        "{{ '42'|int }}",
+        json::object(),
+        "42"
+    );
+
+    test_template(t, "int from string with default",
+        "{{ ''|int(1) }}",
+        json::object(),
+        "1"
+    );
+
+    test_template(t, "int from string with base",
+        "{{ '11'|int(base=2) }}",
+        json::object(),
+        "3"
+    );
+
+    test_template(t, "float from string",
+        "{{ '3.14'|float }}",
+        json::object(),
+        "3.14"
+    );
+
+    test_template(t, "default with value",
+        "{{ x|default('fallback') }}",
+        {{"x", "actual"}},
+        "actual"
+    );
+
+    test_template(t, "default without value",
+        "{{ y|default('fallback') }}",
+        json::object(),
+        "fallback"
+    );
+
+    test_template(t, "default with falsy value",
+        "{{ ''|default('fallback', true) }}",
+        json::object(),
+        "fallback"
+    );
+
+    test_template(t, "tojson ensure_ascii=true",
+        "{{ data|tojson(ensure_ascii=true) }}",
+        {{"data", "\u2713"}},
+        "\"\\u2713\""
+    );
+
+    test_template(t, "tojson sort_keys=true",
+        "{{ data|tojson(sort_keys=true) }}",
+        {{"data", {{"b", 2}, {"a", 1}}}},
+        "{\"a\": 1, \"b\": 2}"
+    );
+
+    test_template(t, "tojson",
+        "{{ data|tojson }}",
+        {{"data", {{"a", 1}, {"b", json::array({1, 2})}}}},
+        "{\"a\": 1, \"b\": [1, 2]}"
+    );
+
+    test_template(t, "tojson indent=4",
+        "{{ data|tojson(indent=4) }}",
+        {{"data", {{"a", 1}, {"b", json::array({1, 2})}}}},
+        "{\n    \"a\": 1,\n    \"b\": [\n        1,\n        2\n    ]\n}"
+    );
+
+    test_template(t, "tojson separators=(',',':')",
+        "{{ data|tojson(separators=(',',':')) }}",
+        {{"data", {{"a", 1}, {"b", json::array({1, 2})}}}},
+        "{\"a\":1,\"b\":[1,2]}"
+    );
+
+    test_template(t, "tojson separators=(',',': ') indent=2",
+        "{{ data|tojson(separators=(',',': '), indent=2) }}",
+        {{"data", {{"a", 1}, {"b", json::array({1, 2})}}}},
+        "{\n  \"a\": 1,\n  \"b\": [\n    1,\n    2\n  ]\n}"
+    );
+
+    test_template(t, "chained filters",
+        "{{ '  HELLO  '|trim|lower }}",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "none to string",
+        "{{ x|string }}",
+        {{"x", nullptr}},
+        "None"
+    );
+}
+
+static void test_literals(testing & t) {
+    test_template(t, "integer",
+        "{{ 42 }}",
+        json::object(),
+        "42"
+    );
+
+    test_template(t, "float",
+        "{{ 3.14 }}",
+        json::object(),
+        "3.14"
+    );
+
+    test_template(t, "string",
+        "{{ 'hello' }}",
+        json::object(),
+        "hello"
+    );
+
+    test_template(t, "boolean true",
+        "{{ true }}",
+        json::object(),
+        "True"
+    );
+
+    test_template(t, "boolean false",
+        "{{ false }}",
+        json::object(),
+        "False"
+    );
+
+    test_template(t, "none",
+        "{% if x is none %}null{% endif %}",
+        {{"x", nullptr}},
+        "null"
+    );
+
+    test_template(t, "list literal",
+        "{% for i in [1, 2, 3] %}{{ i }}{% endfor %}",
+        json::object(),
+        "123"
+    );
+
+    test_template(t, "dict literal",
+        "{% set d = {'a': 1} %}{{ d.a }}",
+        json::object(),
+        "1"
+    );
+
+    test_template(t, "integer|abs",
+        "{{ -42 | abs }}",
+        json::object(),
+        "42"
+    );
+
+    test_template(t, "integer|float",
+        "{{ 42 | float }}",
+        json::object(),
+        "42.0"
+    );
+
+    test_template(t, "integer|tojson",
+        "{{ 42 | tojson }}",
+        json::object(),
+        "42"
+    );
+
+    test_template(t, "float|abs",
+        "{{ -3.14 | abs }}",
+        json::object(),
+        "3.14"
+    );
+
+    test_template(t, "float|int",
+        "{{ 3.14 | int }}",
+        json::object(),
+        "3"
+    );
+
+    test_template(t, "float|tojson",
+        "{{ 3.14 | tojson }}",
+        json::object(),
+        "3.14"
+    );
+
+    test_template(t, "string|tojson",
+        "{{ 'hello' | tojson }}",
+        json::object(),
+        "\"hello\""
+    );
+
+    test_template(t, "boolean|int",
+        "{{ true | int }}",
+        json::object(),
+        "1"
+    );
+
+    test_template(t, "boolean|float",
+        "{{ true | float }}",
+        json::object(),
+        "1.0"
+    );
+
+    test_template(t, "boolean|tojson",
+        "{{ true | tojson }}",
+        json::object(),
+        "true"
+    );
+}
+
+static void test_comments(testing & t) {
+    test_template(t, "inline comment",
+        "before{# comment #}after",
+        json::object(),
+        "beforeafter"
+    );
+
+    test_template(t, "comment ignores code",
+        "{% set x = 1 %}{# {% set x = 999 %} #}{{ x }}",
+        json::object(),
+        "1"
+    );
+}
+
+static void test_macros(testing & t) {
+    test_template(t, "simple macro",
+        "{% macro greet(name) %}Hello {{ name }}{% endmacro %}{{ greet('World') }}",
+        json::object(),
+        "Hello World"
+    );
+
+    test_template(t, "macro default arg",
+        "{% macro greet(name='Guest') %}Hi {{ name }}{% endmacro %}{{ greet() }}",
+        json::object(),
+        "Hi Guest"
+    );
+}
+
+static void test_namespace(testing & t) {
+    test_template(t, "namespace counter",
+        "{% set ns = namespace(count=0) %}{% for i in range(3) %}{% set ns.count = ns.count + 1 %}{% endfor %}{{ ns.count }}",
+        json::object(),
+        "3"
+    );
+}
+
+static void test_tests(testing & t) {
+    test_template(t, "is odd",
+        "{% if 3 is odd %}yes{% endif %}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is even",
+        "{% if 4 is even %}yes{% endif %}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is false",
+        "{{ 'yes' if x is false }}",
+        {{"x", false}},
+        "yes"
+    );
+
+    test_template(t, "is true",
+        "{{ 'yes' if x is true }}",
+        {{"x", true}},
+        "yes"
+    );
+
+    test_template(t, "string is false",
+        "{{ 'yes' if x is false else 'no' }}",
+        {{"x", ""}},
+        "no"
+    );
+
+    test_template(t, "is divisibleby",
+        "{{ 'yes' if x is divisibleby(2) }}",
+        {{"x", 2}},
+        "yes"
+    );
+
+    test_template(t, "is eq",
+        "{{ 'yes' if 3 is eq(3) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is not equalto",
+        "{{ 'yes' if 3 is not equalto(4) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is ge",
+        "{{ 'yes' if 3 is ge(3) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is gt",
+        "{{ 'yes' if 3 is gt(2) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is greaterthan",
+        "{{ 'yes' if 3 is greaterthan(2) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is lt",
+        "{{ 'yes' if 2 is lt(3) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is lessthan",
+        "{{ 'yes' if 2 is lessthan(3) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is ne",
+        "{{ 'yes' if 2 is ne(3) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is lower",
+        "{{ 'yes' if 'lowercase' is lower }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is upper",
+        "{{ 'yes' if 'UPPERCASE' is upper }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is sameas",
+        "{{ 'yes' if x is sameas(false) }}",
+        {{"x", false}},
+        "yes"
+    );
+
+    test_template(t, "is boolean",
+        "{{ 'yes' if x is boolean }}",
+        {{"x", true}},
+        "yes"
+    );
+
+    test_template(t, "is callable",
+        "{{ 'yes' if ''.strip is callable }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is escaped",
+        "{{ 'yes' if 'foo'|safe is escaped }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is filter",
+        "{{ 'yes' if 'trim' is filter }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is float",
+        "{{ 'yes' if x is float }}",
+        {{"x", 1.1}},
+        "yes"
+    );
+
+    test_template(t, "is integer",
+        "{{ 'yes' if x is integer }}",
+        {{"x", 1}},
+        "yes"
+    );
+
+    test_template(t, "is sequence",
+        "{{ 'yes' if x is sequence }}",
+        {{"x", json::array({1, 2, 3})}},
+        "yes"
+    );
+
+    test_template(t, "is test",
+        "{{ 'yes' if 'sequence' is test }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is undefined",
+        "{{ 'yes' if x is undefined }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is none",
+        "{% if x is none %}yes{% endif %}",
+        {{"x", nullptr}},
+        "yes"
+    );
+
+    test_template(t, "is string",
+        "{% if x is string %}yes{% endif %}",
+        {{"x", "hello"}},
+        "yes"
+    );
+
+    test_template(t, "is number",
+        "{% if x is number %}yes{% endif %}",
+        {{"x", 42}},
+        "yes"
+    );
+
+    test_template(t, "is iterable",
+        "{% if x is iterable %}yes{% endif %}",
+        {{"x", json::array({1, 2, 3})}},
+        "yes"
+    );
+
+    test_template(t, "is mapping",
+        "{% if x is mapping %}yes{% endif %}",
+        {{"x", {{"a", 1}}}},
+        "yes"
+    );
+
+    test_template(t, "undefined is sequence",
+        "{{ 'yes' if x is sequence }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "undefined is iterable",
+        "{{ 'yes' if x is iterable }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is in (array, true)",
+        "{{ 'yes' if 2 is in([1, 2, 3]) }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is in (array, false)",
+        "{{ 'yes' if 5 is in([1, 2, 3]) else 'no' }}",
+        json::object(),
+        "no"
+    );
+
+    test_template(t, "is in (string)",
+        "{{ 'yes' if 'bc' is in('abcde') }}",
+        json::object(),
+        "yes"
+    );
+
+    test_template(t, "is in (object keys)",
+        "{{ 'yes' if 'a' is in(obj) }}",
+        {{"obj", {{"a", 1}, {"b", 2}}}},
+        "yes"
+    );
+
+    test_template(t, "reject with in test",
+        "{{ items | reject('in', skip) | join(', ') }}",
+        {{"items", json::array({"a", "b", "c", "d"})}, {"skip", json::array({"b", "d"})}},
+        "a, c"
+    );
+
+    test_template(t, "select with in test",
+        "{{ items | select('in', keep) | join(', ') }}",
+        {{"items", json::array({"a", "b", "c", "d"})}, {"keep", json::array({"b", "c"})}},
+        "b, c"
+    );
+}
+
+static void test_string_methods(testing & t) {
+    test_template(t, "string.upper()",
+        "{{ s.upper() }}",
+        {{"s", "hello"}},
+        "HELLO"
+    );
+
+    test_template(t, "string.lower()",
+        "{{ s.lower() }}",
+        {{"s", "HELLO"}},
+        "hello"
+    );
+
+    test_template(t, "string.strip()",
+        "[{{ s.strip() }}]",
+        {{"s", "  hello  "}},
+        "[hello]"
+    );
+
+    test_template(t, "string.lstrip()",
+        "[{{ s.lstrip() }}]",
+        {{"s", "   hello"}},
+        "[hello]"
+    );
+
+    test_template(t, "string.rstrip()",
+        "[{{ s.rstrip() }}]",
+        {{"s", "hello   "}},
+        "[hello]"
+    );
+
+    test_template(t, "string.title()",
+        "{{ s.title() }}",
+        {{"s", "hello world"}},
+        "Hello World"
+    );
+
+    test_template(t, "string.capitalize()",
+        "{{ s.capitalize() }}",
+        {{"s", "heLlo World"}},
+        "Hello world"
+    );
+
+    test_template(t, "string.startswith() true",
+        "{% if s.startswith('hel') %}yes{% endif %}",
+        {{"s", "hello"}},
+        "yes"
+    );
+
+    test_template(t, "string.startswith() false",
+        "{% if s.startswith('xyz') %}yes{% else %}no{% endif %}",
+        {{"s", "hello"}},
+        "no"
+    );
+
+    test_template(t, "string.endswith() true",
+        "{% if s.endswith('lo') %}yes{% endif %}",
+        {{"s", "hello"}},
+        "yes"
+    );
+
+    test_template(t, "string.endswith() false",
+        "{% if s.endswith('xyz') %}yes{% else %}no{% endif %}",
+        {{"s", "hello"}},
+        "no"
+    );
+
+    test_template(t, "string.split() with sep",
+        "{{ s.split(',')|join('-') }}",
+        {{"s", "a,b,c"}},
+        "a-b-c"
+    );
+
+    test_template(t, "string.split() with maxsplit",
+        "{{ s.split(',', 1)|join('-') }}",
+        {{"s", "a,b,c"}},
+        "a-b,c"
+    );
+
+    test_template(t, "string.rsplit() with sep",
+        "{{ s.rsplit(',')|join('-') }}",
+        {{"s", "a,b,c"}},
+        "a-b-c"
+    );
+
+    test_template(t, "string.rsplit() with maxsplit",
+        "{{ s.rsplit(',', 1)|join('-') }}",
+        {{"s", "a,b,c"}},
+        "a,b-c"
+    );
+
+    test_template(t, "string.replace() basic",
+        "{{ s.replace('world', 'jinja') }}",
+        {{"s", "hello world"}},
+        "hello jinja"
+    );
+
+    test_template(t, "string.replace() with count",
+        "{{ s.replace('a', 'X', 2) }}",
+        {{"s", "banana"}},
+        "bXnXna"
+    );
+
+    test_template(t, "undefined|capitalize",
+        "{{ arr|capitalize }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|title",
+        "{{ arr|title }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|truncate",
+        "{{ arr|truncate(9) }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|upper",
+        "{{ arr|upper }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|lower",
+        "{{ arr|lower }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|replace",
+        "{{ arr|replace('a', 'b') }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|trim",
+        "{{ arr|trim }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|wordcount",
+        "{{ arr|wordcount }}",
+        json::object(),
+        "0"
+    );
+}
+
+static void test_array_methods(testing & t) {
+    test_template(t, "array|selectattr by attribute",
+        "{% for item in items|selectattr('active') %}{{ item.name }} {% endfor %}",
+        {{"items", json::array({
+            {{"name", "a"}, {"active", true}},
+            {{"name", "b"}, {"active", false}},
+            {{"name", "c"}, {"active", true}}
+        })}},
+        "a c "
+    );
+
+    test_template(t, "array|selectattr with operator",
+        "{% for item in items|selectattr('value', 'equalto', 5) %}{{ item.name }} {% endfor %}",
+        {{"items", json::array({
+            {{"name", "a"}, {"value", 3}},
+            {{"name", "b"}, {"value", 5}},
+            {{"name", "c"}, {"value", 5}}
+        })}},
+        "b c "
+    );
+
+    test_template(t, "array|tojson",
+        "{{ arr|tojson }}",
+        {{"arr", json::array({1, 2, 3})}},
+        "[1, 2, 3]"
+    );
+
+    test_template(t, "array|tojson with strings",
+        "{{ arr|tojson }}",
+        {{"arr", json::array({"a", "b", "c"})}},
+        "[\"a\", \"b\", \"c\"]"
+    );
+
+    test_template(t, "array|tojson nested",
+        "{{ arr|tojson }}",
+        {{"arr", json::array({json::array({1, 2}), json::array({3, 4})})}},
+        "[[1, 2], [3, 4]]"
+    );
+
+    test_template(t, "array|last",
+        "{{ arr|last }}",
+        {{"arr", json::array({10, 20, 30})}},
+        "30"
+    );
+
+    test_template(t, "array|last single element",
+        "{{ arr|last }}",
+        {{"arr", json::array({42})}},
+        "42"
+    );
+
+    test_template(t, "array|join with separator",
+        "{{ arr|join(', ') }}",
+        {{"arr", json::array({"a", "b", "c"})}},
+        "a, b, c"
+    );
+
+    test_template(t, "array|join with custom separator",
+        "{{ arr|join(' | ') }}",
+        {{"arr", json::array({1, 2, 3})}},
+        "1 | 2 | 3"
+    );
+
+    test_template(t, "array|join default separator",
+        "{{ arr|join }}",
+        {{"arr", json::array({"x", "y", "z"})}},
+        "xyz"
+    );
+
+    test_template(t, "array|join attribute",
+        "{{ arr|join(attribute='age') }}",
+        {{"arr", json::array({
+            json({{"name", "a"}, {"age", 1}}),
+            json({{"name", "b"}, {"age", 2}}),
+            json({{"name", "c"}, {"age", 3}}),
+        })}},
+        "123"
+    );
+
+    test_template(t, "array|join numeric attribute",
+        "{{ arr|join(attribute=-1) }}",
+        {{"arr", json::array({json::array({1}), json::array({2}), json::array({3})})}},
+        "123"
+    );
+
+    test_template(t, "array.pop() last",
+        "{{ arr.pop() }}-{{ arr|join(',') }}",
+        {{"arr", json::array({"a", "b", "c"})}},
+        "c-a,b"
+    );
+
+    test_template(t, "array.pop() with index",
+        "{{ arr.pop(0) }}-{{ arr|join(',') }}",
+        {{"arr", json::array({"a", "b", "c"})}},
+        "a-b,c"
+    );
+
+    test_template(t, "array.append()",
+        "{% set _ = arr.append('d') %}{{ arr|join(',') }}",
+        {{"arr", json::array({"a", "b", "c"})}},
+        "a,b,c,d"
+    );
+
+    test_template(t, "array|map with attribute",
+        "{% for v in arr|map(attribute='age') %}{{ v }} {% endfor %}",
+        {{"arr", json::array({
+            json({{"name", "a"}, {"age", 1}}),
+            json({{"name", "b"}, {"age", 2}}),
+            json({{"name", "c"}, {"age", 3}}),
+        })}},
+        "1 2 3 "
+    );
+
+    test_template(t, "array|map with attribute default",
+        "{% for v in arr|map(attribute='age', default=3) %}{{ v }} {% endfor %}",
+        {{"arr", json::array({
+            json({{"name", "a"}, {"age", 1}}),
+            json({{"name", "b"}, {"age", 2}}),
+            json({{"name", "c"}}),
+        })}},
+        "1 2 3 "
+    );
+
+    test_template(t, "array|map without attribute default",
+        "{% for v in arr|map(attribute='age') %}{{ v }} {% endfor %}",
+        {{"arr", json::array({
+            json({{"name", "a"}, {"age", 1}}),
+            json({{"name", "b"}, {"age", 2}}),
+            json({{"name", "c"}}),
+        })}},
+        "1 2  "
+    );
+
+    test_template(t, "array|map with numeric attribute",
+        "{% for v in arr|map(attribute=0) %}{{ v }} {% endfor %}",
+        {{"arr", json::array({
+            json::array({10, "x"}),
+            json::array({20, "y"}),
+            json::array({30, "z"}),
+        })}},
+        "10 20 30 "
+    );
+
+    test_template(t, "array|map with negative attribute",
+        "{% for v in arr|map(attribute=-1) %}{{ v }} {% endfor %}",
+        {{"arr", json::array({
+            json::array({10, "x"}),
+            json::array({20, "y"}),
+            json::array({30, "z"}),
+        })}},
+        "x y z "
+    );
+
+    test_template(t, "array|map with filter",
+        "{{ arr|map('int')|sum }}",
+        {{"arr", json::array({"1", "2", "3"})}},
+        "6"
+    );
+
+    // not used by any chat templates
+    // test_template(t, "array.insert()",
+    //     "{% set _ = arr.insert(1, 'x') %}{{ arr|join(',') }}",
+    //     {{"arr", json::array({"a", "b", "c"})}},
+    //     "a,x,b,c"
+    // );
+
+    test_template(t, "undefined|select",
+        "{% for item in items|select('odd') %}{{ item.name }} {% endfor %}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|selectattr",
+        "{% for item in items|selectattr('active') %}{{ item.name }} {% endfor %}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|reject",
+        "{% for item in items|reject('even') %}{{ item.name }} {% endfor %}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|rejectattr",
+        "{% for item in items|rejectattr('active') %}{{ item.name }} {% endfor %}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|list",
+        "{{ arr|list|string }}",
+        json::object(),
+        "[]"
+    );
+
+    test_template(t, "undefined|string",
+        "{{ arr|string }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|first",
+        "{{ arr|first }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|last",
+        "{{ arr|last }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|length",
+        "{{ arr|length }}",
+        json::object(),
+        "0"
+    );
+
+    test_template(t, "undefined|join",
+        "{{ arr|join }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|sort",
+        "{{ arr|sort|string }}",
+        json::object(),
+        "[]"
+    );
+
+    test_template(t, "undefined|reverse",
+        "{{ arr|reverse|join }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|map",
+        "{% for v in arr|map(attribute='age') %}{{ v }} {% endfor %}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|min",
+        "{{ arr|min }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|max",
+        "{{ arr|max }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|unique",
+        "{{ arr|unique|join }}",
+        json::object(),
+        ""
+    );
+
+    test_template(t, "undefined|sum",
+        "{{ arr|sum }}",
+        json::object(),
+        "0"
+    );
+}
+
+static void test_object_methods(testing & t) {
+    test_template(t, "object.get() existing key",
+        "{{ obj.get('a') }}",
+        {{"obj", {{"a", 1}, {"b", 2}}}},
+        "1"
+    );
+
+    test_template(t, "object.get() missing key",
+        "[{{ obj.get('c') is none }}]",
+        {{"obj", {{"a", 1}}}},
+        "[True]"
+    );
+
+    test_template(t, "object.get() missing key with default",
+        "{{ obj.get('c', 'default') }}",
+        {{"obj", {{"a", 1}}}},
+        "default"
+    );
+
+    test_template(t, "object.items()",
+        "{% for k, v in obj.items() %}{{ k }}={{ v }} {% endfor %}",
+        {{"obj", {{"x", 1}, {"y", 2}}}},
+        "x=1 y=2 "
+    );
+
+    test_template(t, "object.keys()",
+        "{% for k in obj.keys() %}{{ k }} {% endfor %}",
+        {{"obj", {{"a", 1}, {"b", 2}}}},
+        "a b "
+    );
+
+    test_template(t, "object.values()",
+        "{% for v in obj.values() %}{{ v }} {% endfor %}",
+        {{"obj", {{"a", 1}, {"b", 2}}}},
+        "1 2 "
+    );
+
+    test_template(t, "dictsort ascending by key",
+        "{% for k, v in obj|dictsort %}{{ k }}={{ v }} {% endfor %}",
+        {{"obj", {{"z", 2}, {"a", 3}, {"m", 1}}}},
+        "a=3 m=1 z=2 "
+    );
+
+    test_template(t, "dictsort descending by key",
+        "{% for k, v in obj|dictsort(reverse=true) %}{{ k }}={{ v }} {% endfor %}",
+        {{"obj", {{"a", 1}, {"b", 2}, {"c", 3}}}},
+        "c=3 b=2 a=1 "
+    );
+
+    test_template(t, "dictsort by value",
+        "{% for k, v in obj|dictsort(by='value') %}{{ k }}={{ v }} {% endfor %}",
+        {{"obj", {{"a", 3}, {"b", 1}, {"c", 2}}}},
+        "b=1 c=2 a=3 "
+    );
+
+    test_template(t, "dictsort case sensitive",
+        "{% for k, v in obj|dictsort(case_sensitive=true) %}{{ k }}={{ v }} {% endfor %}",
+        {{"obj", {{"a", 1}, {"A", 1}, {"b", 2}, {"B", 2}, {"c", 3}}}},
+        "A=1 B=2 a=1 b=2 c=3 "
+    );
+
+    test_template(t, "object|tojson",
+        "{{ obj|tojson }}",
+        {{"obj", {{"name", "test"}, {"value", 42}}}},
+        "{\"name\": \"test\", \"value\": 42}"
+    );
+
+    test_template(t, "nested object|tojson",
+        "{{ obj|tojson }}",
+        {{"obj", {{"outer", {{"inner", "value"}}}}}},
+        "{\"outer\": {\"inner\": \"value\"}}"
+    );
+
+    test_template(t, "array in object|tojson",
+        "{{ obj|tojson }}",
+        {{"obj", {{"items", json::array({1, 2, 3})}}}},
+        "{\"items\": [1, 2, 3]}"
+    );
+
+    test_template(t, "object attribute and key access",
+        "{{ obj.keys()|join(',') }} vs {{ obj['keys'] }} vs {{ obj.test }}",
+        {{"obj", {{"keys", "value"}, {"test", "attr_value"}}}},
+        "keys,test vs value vs attr_value"
+    );
+
+    test_template(t, "env should not have object methods",
+        "{{ keys is undefined }} {{ obj.keys is defined }}",
+        {{"obj", {{"a", "b"}}}},
+        "True True"
+    );
+
+    test_template(t, "expression as object key",
+        "{% set d = {'ab': 123} %}{{ d['a' + 'b'] == 123 }}",
+        json::object(),
+        "True"
+    );
+
+    test_template(t, "numeric as object key (template: Seed-OSS)",
+        "{% set d = {1: 'a', 2: 'b'} %}{{ d[1] == 'a' and d[2] == 'b' }}",
+        json::object(),
+        "True"
+    );
+
+    test_template(t, "undefined|items",
+        "{{ arr|items|join }}",
+        json::object(),
+        ""
+    );
+}
+
+static void test_hasher(testing & t) {
+    static const std::vector<std::pair<size_t, size_t>> chunk_sizes = {
+        {1, 2},
+        {1, 16},
+        {8, 1},
+        {1, 1024},
+        {5, 512},
+        {16, 256},
+        {45, 122},
+        {70, 634},
+    };
+
+    static auto random_bytes = [](size_t length) -> std::string {
+        std::string data;
+        data.resize(length);
+        for (size_t i = 0; i < length; ++i) {
+            data[i] = static_cast<char>(rand() % 256);
+        }
+        return data;
+    };
+
+    t.test("state unchanged with empty input", [](testing & t) {
+        jinja::hasher hasher;
+        hasher.update("some data");
+        size_t initial_state = hasher.digest();
+        hasher.update("", 0);
+        size_t final_state = hasher.digest();
+        t.assert_true("Hasher state should remain unchanged", initial_state == final_state);
+    });
+
+    t.test("different inputs produce different hashes", [](testing & t) {
+        jinja::hasher hasher1;
+        hasher1.update("data one");
+        size_t hash1 = hasher1.digest();
+
+        jinja::hasher hasher2;
+        hasher2.update("data two");
+        size_t hash2 = hasher2.digest();
+
+        t.assert_true("Different inputs should produce different hashes", hash1 != hash2);
+    });
+
+    t.test("same inputs produce same hashes", [](testing & t) {
+        jinja::hasher hasher1;
+        hasher1.update("consistent data");
+        size_t hash1 = hasher1.digest();
+
+        jinja::hasher hasher2;
+        hasher2.update("consistent data");
+        size_t hash2 = hasher2.digest();
+
+        t.assert_true("Same inputs should produce same hashes", hash1 == hash2);
+    });
+
+    t.test("property: update(a ~ b) == update(a).update(b)", [](testing & t) {
+        for (const auto & [size1, size2] : chunk_sizes) {
+            std::string data1 = random_bytes(size1);
+            std::string data2 = random_bytes(size2);
+
+            jinja::hasher hasher1;
+            hasher1.update(data1);
+            hasher1.update(data2);
+            size_t hash1 = hasher1.digest();
+
+            jinja::hasher hasher2;
+            hasher2.update(data1 + data2);
+            size_t hash2 = hasher2.digest();
+
+            t.assert_true(
+                "Hashing in multiple updates should match single update (" + std::to_string(size1) + ", " + std::to_string(size2) + ")",
+                hash1 == hash2);
+        }
+    });
+
+    t.test("property: update(a ~ b) == update(a).update(b) with more update passes", [](testing & t) {
+        static const std::vector<size_t> sizes = {3, 732, 131, 13, 17, 256, 436, 99, 4};
+
+        jinja::hasher hasher1;
+        jinja::hasher hasher2;
+
+        std::string combined_data;
+        for (size_t size : sizes) {
+            std::string data = random_bytes(size);
+            hasher1.update(data);
+            combined_data += data;
+        }
+
+        hasher2.update(combined_data);
+        size_t hash1 = hasher1.digest();
+        size_t hash2 = hasher2.digest();
+        t.assert_true(
+            "Hashing in multiple updates should match single update with many chunks",
+            hash1 == hash2);
+    });
+
+    t.test("property: non associativity of update", [](testing & t) {
+        for (const auto & [size1, size2] : chunk_sizes) {
+            std::string data1 = random_bytes(size1);
+            std::string data2 = random_bytes(size2);
+
+            jinja::hasher hasher1;
+            hasher1.update(data1);
+            hasher1.update(data2);
+            size_t hash1 = hasher1.digest();
+
+            jinja::hasher hasher2;
+            hasher2.update(data2);
+            hasher2.update(data1);
+            size_t hash2 = hasher2.digest();
+
+            t.assert_true(
+                "Hashing order should matter (" + std::to_string(size1) + ", " + std::to_string(size2) + ")",
+                hash1 != hash2);
+        }
+    });
+
+    t.test("property: different lengths produce different hashes (padding block size)", [](testing & t) {
+        std::string random_data = random_bytes(64);
+
+        jinja::hasher hasher1;
+        hasher1.update(random_data);
+        size_t hash1 = hasher1.digest();
+
+        for (int i = 0; i < 16; ++i) {
+            random_data.push_back('A');  // change length
+            jinja::hasher hasher2;
+            hasher2.update(random_data);
+            size_t hash2 = hasher2.digest();
+
+            t.assert_true("Different lengths should produce different hashes (length " + std::to_string(random_data.size()) + ")", hash1 != hash2);
+
+            hash1 = hash2;
+        }
+    });
+}
+
+static void test_template_cpp(testing & t, const std::string & name, const std::string & tmpl, const json & vars, const std::string & expect) {
+    t.test(name, [&tmpl, &vars, &expect](testing & t) {
+        jinja::lexer lexer;
+        auto lexer_res = lexer.tokenize(tmpl);
+
+        jinja::program ast = jinja::parse_from_tokens(lexer_res);
+
+        jinja::context ctx(tmpl);
+        jinja::global_from_json(ctx, vars, true);
+
+        jinja::runtime runtime(ctx);
+
+        try {
+            const jinja::value results = runtime.execute(ast);
+            auto parts = runtime.gather_string_parts(results);
+
+            std::string rendered;
+            for (const auto & part : parts->as_string().parts) {
+                rendered += part.val;
+            }
+
+            if (!t.assert_true("Template render mismatch", expect == rendered)) {
+                t.log("Template: " + json(tmpl).dump());
+                t.log("Expected: " + json(expect).dump());
+                t.log("Actual  : " + json(rendered).dump());
+            }
+        } catch (const jinja::not_implemented_exception & e) {
+            // TODO @ngxson : remove this when the test framework supports skipping tests
+            t.log("Skipped: " + std::string(e.what()));
+        }
+    });
+}
+
+// keep this in-sync with https://github.com/huggingface/transformers/blob/main/src/transformers/utils/chat_template_utils.py
+// note: we use SandboxedEnvironment instead of ImmutableSandboxedEnvironment to allow usage of in-place array methods like append() and pop()
+static std::string py_script = R"(
+import jinja2
+import jinja2.ext as jinja2_ext
+import json
+import sys
+from datetime import datetime
+from jinja2.sandbox import SandboxedEnvironment
+
+tmpl = json.loads(sys.argv[1])
+vars_json = json.loads(sys.argv[2])
+
+env = SandboxedEnvironment(
+    trim_blocks=True,
+    lstrip_blocks=True,
+    extensions=[jinja2_ext.loopcontrols],
+)
+
+def raise_exception(message):
+    raise jinja2.exceptions.TemplateError(message)
+
+env.filters["tojson"] = lambda x, ensure_ascii=False, indent=None, separators=None, sort_keys=False: json.dumps(x, ensure_ascii=ensure_ascii, indent=indent, separators=separators, sort_keys=sort_keys)
+env.globals["strftime_now"] = lambda format: datetime.now().strftime(format)
+env.globals["raise_exception"] = raise_exception
+
+template = env.from_string(tmpl)
+result = template.render(**vars_json)
+print(result, end='')
+)";
+
+static void test_template_py(testing & t, const std::string & name, const std::string & tmpl, const json & vars, const std::string & expect) {
+    t.test(name, [&tmpl, &vars, &expect](testing & t) {
+        // Prepare arguments
+        std::string tmpl_json = json(tmpl).dump();
+        std::string vars_json = vars.dump();
+
+#ifdef _WIN32
+        const char * python_executable = "python.exe";
+#else
+        const char * python_executable = "python3";
+#endif
+
+        const char * command_line[] = {python_executable, "-c", py_script.c_str(), tmpl_json.c_str(), vars_json.c_str(), NULL};
+
+        struct subprocess_s subprocess;
+        int options = subprocess_option_combined_stdout_stderr
+                    | subprocess_option_no_window
+                    | subprocess_option_inherit_environment
+                    | subprocess_option_search_user_path;
+        int result = subprocess_create(command_line, options, &subprocess);
+
+        if (result != 0) {
+            t.log("Failed to create subprocess, error code: " + std::to_string(result));
+            t.assert_true("subprocess creation", false);
+            return;
+        }
+
+        // Read output
+        std::string output;
+        char buffer[1024];
+        FILE * p_stdout = subprocess_stdout(&subprocess);
+        while (fgets(buffer, sizeof(buffer), p_stdout)) {
+            output += buffer;
+        }
+
+        int process_return;
+        subprocess_join(&subprocess, &process_return);
+        subprocess_destroy(&subprocess);
+
+        if (process_return != 0) {
+            t.log("Python script failed with exit code: " + std::to_string(process_return));
+            t.log("Output: " + output);
+            t.assert_true("python execution", false);
+            return;
+        }
+
+        if (!t.assert_true("Template render mismatch", expect == output)) {
+            t.log("Template: " + json(tmpl).dump());
+            t.log("Expected: " + json(expect).dump());
+            t.log("Python  : " + json(output).dump());
+        }
+    });
+}
+
+static void test_template(testing & t, const std::string & name, const std::string & tmpl, const json & vars, const std::string & expect) {
+    if (g_python_mode) {
+        test_template_py(t, name, tmpl, vars, expect);
+    } else {
+        test_template_cpp(t, name, tmpl, vars, expect);
+    }
+}
+
+//
+// fuzz tests to ensure no crashes occur on malformed inputs
+//
+
+constexpr int JINJA_FUZZ_ITERATIONS = 100;
+
+// Helper to generate random string
+static std::string random_string(std::mt19937 & rng, size_t max_len) {
+    static const char charset[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
+    std::uniform_int_distribution<size_t> len_dist(0, max_len);
+    std::uniform_int_distribution<size_t> char_dist(0, sizeof(charset) - 2);
+    size_t len = len_dist(rng);
+    std::string result;
+    result.reserve(len);
+    for (size_t i = 0; i < len; ++i) {
+        result += charset[char_dist(rng)];
+    }
+    return result;
+}
+
+// Helper to execute a fuzz test case - returns true if no crash occurred
+static bool fuzz_test_template(const std::string & tmpl, const json & vars) {
+    try {
+        // printf("Fuzz testing template: %s\n", tmpl.c_str());
+        jinja::lexer lexer;
+        auto lexer_res = lexer.tokenize(tmpl);
+        jinja::program ast = jinja::parse_from_tokens(lexer_res);
+        jinja::context ctx(tmpl);
+        jinja::global_from_json(ctx, vars, true);
+        jinja::runtime runtime(ctx);
+        const jinja::value results = runtime.execute(ast);
+        runtime.gather_string_parts(results);
+        return true; // success
+    } catch (const std::exception &) {
+        return true; // exception is acceptable, not a crash
+    } catch (...) {
+        return true; // any exception is acceptable, not a crash
+    }
+}
+
+static void test_fuzzing(testing & t) {
+    const int num_iterations = JINJA_FUZZ_ITERATIONS;
+    const unsigned int seed = 42; // fixed seed for reproducibility
+    std::mt19937 rng(seed);
+
+    // Distribution helpers
+    std::uniform_int_distribution<int> choice_dist(0, 100);
+    std::uniform_int_distribution<int> int_dist(-1000, 1000);
+    std::uniform_int_distribution<size_t> idx_dist(0, 1000);
+
+    // Template fragments for fuzzing
+    const std::vector<std::string> var_names = {
+        "x", "y", "z", "arr", "obj", "items", "foo", "bar", "undefined_var",
+        "none", "true", "false", "None", "True", "False"
+    };
+    const std::vector<std::string> filters = {
+        "length", "first", "last", "reverse", "sort", "unique", "join", "upper", "lower",
+        "trim", "default", "tojson", "string", "int", "float", "abs", "list", "dictsort"
+    };
+    const std::vector<std::string> builtins = {
+        "range", "len", "dict", "list", "join", "str", "int", "float", "namespace"
+    };
+
+    t.test("out of bound array access", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            int idx = int_dist(rng);
+            std::string tmpl = "{{ arr[" + std::to_string(idx) + "] }}";
+            json vars = {{"arr", json::array({1, 2, 3})}};
+            t.assert_true("should not crash", fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("non-existing variables", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            std::string var = random_string(rng, 20);
+            std::string tmpl = "{{ " + var + " }}";
+            json vars = json::object(); // empty context
+            t.assert_true("should not crash", fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("non-existing nested attributes", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            std::string var1 = var_names[choice_dist(rng) % var_names.size()];
+            std::string var2 = random_string(rng, 10);
+            std::string var3 = random_string(rng, 10);
+            std::string tmpl = "{{ " + var1 + "." + var2 + "." + var3 + " }}";
+            json vars = {{var1, {{"other", 123}}}};
+            t.assert_true("should not crash", fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("invalid filter arguments", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            std::string filter = filters[choice_dist(rng) % filters.size()];
+            int val = int_dist(rng);
+            std::string tmpl = "{{ " + std::to_string(val) + " | " + filter + " }}";
+            json vars = json::object();
+            t.assert_true("should not crash", fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("chained filters on various types", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            std::string f1 = filters[choice_dist(rng) % filters.size()];
+            std::string f2 = filters[choice_dist(rng) % filters.size()];
+            std::string var = var_names[choice_dist(rng) % var_names.size()];
+            std::string tmpl = "{{ " + var + " | " + f1 + " | " + f2 + " }}";
+            json vars = {
+                {"x", 42},
+                {"y", "hello"},
+                {"arr", json::array({1, 2, 3})},
+                {"obj", {{"a", 1}, {"b", 2}}},
+                {"items", json::array({"a", "b", "c"})}
+            };
+            t.assert_true("should not crash", fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("invalid builtin calls", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            std::string builtin = builtins[choice_dist(rng) % builtins.size()];
+            std::string arg;
+            int arg_type = choice_dist(rng) % 4;
+            switch (arg_type) {
+                case 0: arg = "\"not a number\""; break;
+                case 1: arg = "none"; break;
+                case 2: arg = std::to_string(int_dist(rng)); break;
+                case 3: arg = "[]"; break;
+            }
+            std::string tmpl = "{{ " + builtin + "(" + arg + ") }}";
+            json vars = json::object();
+            t.assert_true("should not crash", fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("macro edge cases", [&](testing & t) {
+        // Macro with no args called with args
+        t.assert_true("macro no args with args", fuzz_test_template(
+            "{% macro foo() %}hello{% endmacro %}{{ foo(1, 2, 3) }}",
+            json::object()
+        ));
+
+        // Macro with args called with no args
+        t.assert_true("macro with args no args", fuzz_test_template(
+            "{% macro foo(a, b, c) %}{{ a }}{{ b }}{{ c }}{% endmacro %}{{ foo() }}",
+            json::object()
+        ));
+
+        // Recursive macro reference
+        t.assert_true("recursive macro", fuzz_test_template(
+            "{% macro foo(n) %}{% if n > 0 %}{{ foo(n - 1) }}{% endif %}{% endmacro %}{{ foo(5) }}",
+            json::object()
+        ));
+
+        // Nested macro definitions
+        for (int i = 0; i < num_iterations / 10; ++i) {
+            std::string tmpl = "{% macro outer() %}{% macro inner() %}x{% endmacro %}{{ inner() }}{% endmacro %}{{ outer() }}";
+            t.assert_true("nested macro", fuzz_test_template(tmpl, json::object()));
+        }
+    });
+
+    t.test("empty and none operations", [&](testing & t) {
+        const std::vector<std::string> empty_tests = {
+            "{{ \"\" | first }}",
+            "{{ \"\" | last }}",
+            "{{ [] | first }}",
+            "{{ [] | last }}",
+            "{{ none.attr }}",
+            "{{ none | length }}",
+            "{{ none | default('fallback') }}",
+            "{{ {} | first }}",
+            "{{ {} | dictsort }}",
+        };
+        for (const auto & tmpl : empty_tests) {
+            t.assert_true("empty/none: " + tmpl, fuzz_test_template(tmpl, json::object()));
+        }
+    });
+
+    t.test("arithmetic edge cases", [&](testing & t) {
+        const std::vector<std::string> arith_tests = {
+            "{{ 1 / 0 }}",
+            "{{ 1 // 0 }}",
+            "{{ 1 % 0 }}",
+            "{{ 999999999999999999 * 999999999999999999 }}",
+            "{{ -999999999999999999 - 999999999999999999 }}",
+            "{{ 1.0 / 0.0 }}",
+            "{{ 0.0 / 0.0 }}",
+        };
+        for (const auto & tmpl : arith_tests) {
+            t.assert_true("arith: " + tmpl, fuzz_test_template(tmpl, json::object()));
+        }
+    });
+
+    t.test("deeply nested structures", [&](testing & t) {
+        // Deeply nested loops
+        for (int depth = 1; depth <= 10; ++depth) {
+            std::string tmpl;
+            for (int d = 0; d < depth; ++d) {
+                tmpl += "{% for i" + std::to_string(d) + " in arr %}";
+            }
+            tmpl += "x";
+            for (int d = 0; d < depth; ++d) {
+                tmpl += "{% endfor %}";
+            }
+            json vars = {{"arr", json::array({1, 2})}};
+            t.assert_true("nested loops depth " + std::to_string(depth), fuzz_test_template(tmpl, vars));
+        }
+
+        // Deeply nested conditionals
+        for (int depth = 1; depth <= 10; ++depth) {
+            std::string tmpl;
+            for (int d = 0; d < depth; ++d) {
+                tmpl += "{% if true %}";
+            }
+            tmpl += "x";
+            for (int d = 0; d < depth; ++d) {
+                tmpl += "{% endif %}";
+            }
+            t.assert_true("nested ifs depth " + std::to_string(depth), fuzz_test_template(tmpl, json::object()));
+        }
+    });
+
+    t.test("special characters in strings", [&](testing & t) {
+        const std::vector<std::string> special_tests = {
+            "{{ \"}{%\" }}",
+            "{{ \"}}{{\" }}",
+            "{{ \"{%%}\" }}",
+            "{{ \"\\n\\t\\r\" }}",
+            "{{ \"'\\\"'\" }}",
+            "{{ \"hello\\x00world\" }}",
+        };
+        for (const auto & tmpl : special_tests) {
+            t.assert_true("special: " + tmpl, fuzz_test_template(tmpl, json::object()));
+        }
+    });
+
+    t.test("random template generation", [&](testing & t) {
+        const std::vector<std::string> fragments = {
+            "{{ x }}", "{{ y }}", "{{ arr }}", "{{ obj }}",
+            "{% if true %}a{% endif %}",
+            "{% if false %}b{% else %}c{% endif %}",
+            "{% for i in arr %}{{ i }}{% endfor %}",
+            "{{ x | length }}", "{{ x | first }}", "{{ x | default(0) }}",
+            "{{ x + y }}", "{{ x - y }}", "{{ x * y }}",
+            "{{ x == y }}", "{{ x != y }}", "{{ x > y }}",
+            "{{ range(3) }}", "{{ \"hello\" | upper }}",
+            "text", " ", "\n",
+        };
+
+        for (int i = 0; i < num_iterations; ++i) {
+            std::string tmpl;
+            int num_frags = choice_dist(rng) % 10 + 1;
+            for (int f = 0; f < num_frags; ++f) {
+                tmpl += fragments[choice_dist(rng) % fragments.size()];
+            }
+            json vars = {
+                {"x", int_dist(rng)},
+                {"y", int_dist(rng)},
+                {"arr", json::array({1, 2, 3})},
+                {"obj", {{"a", 1}, {"b", 2}}}
+            };
+            t.assert_true("random template #" + std::to_string(i), fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("malformed templates (should error, not crash)", [&](testing & t) {
+        const std::vector<std::string> malformed = {
+            "{{ x",
+            "{% if %}",
+            "{% for %}",
+            "{% for x in %}",
+            "{% endfor %}",
+            "{% endif %}",
+            "{{ | filter }}",
+            "{% if x %}", // unclosed
+            "{% for i in x %}", // unclosed
+            "{{ x | }}",
+            "{% macro %}{% endmacro %}",
+            "{{{{",
+            "}}}}",
+            "{%%}",
+            "{% set %}",
+            "{% set x %}",
+        };
+        for (const auto & tmpl : malformed) {
+            t.assert_true("malformed: " + tmpl, fuzz_test_template(tmpl, json::object()));
+        }
+    });
+
+    t.test("type coercion edge cases", [&](testing & t) {
+        for (int i = 0; i < num_iterations; ++i) {
+            int op_choice = choice_dist(rng) % 6;
+            std::string op;
+            switch (op_choice) {
+                case 0: op = "+"; break;
+                case 1: op = "-"; break;
+                case 2: op = "*"; break;
+                case 3: op = "/"; break;
+                case 4: op = "=="; break;
+                case 5: op = "~"; break; // string concat
+            }
+
+            std::string left_var = var_names[choice_dist(rng) % var_names.size()];
+            std::string right_var = var_names[choice_dist(rng) % var_names.size()];
+            std::string tmpl = "{{ " + left_var + " " + op + " " + right_var + " }}";
+
+            json vars = {
+                {"x", 42},
+                {"y", "hello"},
+                {"z", 3.14},
+                {"arr", json::array({1, 2, 3})},
+                {"obj", {{"a", 1}}},
+                {"items", json::array()},
+                {"foo", nullptr},
+                {"bar", true}
+            };
+            t.assert_true("type coercion: " + tmpl, fuzz_test_template(tmpl, vars));
+        }
+    });
+
+    t.test("fuzz builtin functions", [&](testing & t) {
+        // pair of (type_name, builtin_name)
+        std::vector<std::pair<std::string, std::string>> builtins;
+        auto add_fns = [&](std::string type_name, const jinja::func_builtins & added) {
+            for (const auto & it : added) {
+                builtins.push_back({type_name, it.first});
+            }
+        };
+        add_fns("global", jinja::global_builtins());
+        add_fns("int",    jinja::value_int_t(0).get_builtins());
+        add_fns("float",  jinja::value_float_t(0.0f).get_builtins());
+        add_fns("string", jinja::value_string_t().get_builtins());
+        add_fns("array",  jinja::value_array_t().get_builtins());
+        add_fns("object", jinja::value_object_t().get_builtins());
+
+        const int max_args = 5;
+        const std::vector<std::string> kwarg_names = {
+            "base", "attribute", "default", "reverse", "case_sensitive", "by", "safe", "chars", "separators", "sort_keys", "indent", "ensure_ascii",
+        };
+
+        // Generate random argument values
+        auto gen_random_arg = [&]() -> std::string {
+            int type = choice_dist(rng) % 8;
+            switch (type) {
+                case 0: return std::to_string(int_dist(rng));           // int
+                case 1: return std::to_string(int_dist(rng)) + ".5";    // float
+                case 2: return "\"" + random_string(rng, 10) + "\"";    // string
+                case 3: return "true";                                   // bool true
+                case 4: return "false";                                  // bool false
+                case 5: return "none";                                   // none
+                case 6: return "[1, 2, 3]";                              // array
+                case 7: return "{\"a\": 1}";                             // object
+                default: return "0";
+            }
+        };
+
+        for (int i = 0; i < num_iterations; ++i) {
+            // Pick a random builtin
+            auto & [type_name, fn_name] = builtins[choice_dist(rng) % builtins.size()];
+
+            // Generate random number of args
+            int num_args = choice_dist(rng) % (max_args + 1);
+            std::string args_str;
+            for (int a = 0; a < num_args; ++a) {
+                if (a > 0) args_str += ", ";
+                // Sometimes use keyword args
+                if (choice_dist(rng) % 3 == 0 && !kwarg_names.empty()) {
+                    std::string kwarg = kwarg_names[choice_dist(rng) % kwarg_names.size()];
+                    args_str += kwarg + "=" + gen_random_arg();
+                } else {
+                    args_str += gen_random_arg();
+                }
+            }
+
+            std::string tmpl;
+            if (type_name == "global") {
+                // Global function call
+                tmpl = "{{ " + fn_name + "(" + args_str + ") }}";
+            } else {
+                // Method call on a value
+                std::string base_val;
+                if (type_name == "int") {
+                    base_val = std::to_string(int_dist(rng));
+                } else if (type_name == "float") {
+                    base_val = std::to_string(int_dist(rng)) + ".5";
+                } else if (type_name == "string") {
+                    base_val = "\"test_string\"";
+                } else if (type_name == "array") {
+                    base_val = "[1, 2, 3, \"a\", \"b\"]";
+                } else if (type_name == "object") {
+                    base_val = "{\"x\": 1, \"y\": 2}";
+                } else {
+                    base_val = "x";
+                }
+                tmpl = "{{ " + base_val + "." + fn_name + "(" + args_str + ") }}";
+            }
+
+            json vars = {
+                {"x", 42},
+                {"y", "hello"},
+                {"arr", json::array({1, 2, 3})},
+                {"obj", {{"a", 1}, {"b", 2}}}
+            };
+
+            t.assert_true("builtin " + type_name + "." + fn_name + " #" + std::to_string(i), fuzz_test_template(tmpl, vars));
+        }
+    });
+}