Testing

What you'll learn

• How the test suite is organized and how to test your own grammars and integrations.

Layout

Tests live inline at the bottom of the source file that implements the functionality — there is no separate tests/ tree:

src/parser/parser.zig    parser, recovery, edits, changed ranges, integration, ranges, streaming, sexp, json, outline, predicates, corpus
src/parser/stack.zig     stack
src/tree/tree.zig        tree properties, copies, ownership
src/tree/node.zig        navigation, fields, ranges
src/tree/cursor.zig      traversal, siblings, reset, copy
src/query/query.zig      queries, matcher semantics, anchors, directives, strictness
src/query/predicate.zig  predicate evaluation (eq/match/contains/any-of/is)
src/query/matcher.zig    subtype expansion, id resolution
src/query/directives.zig select-adjacent, strip
src/language/language.zig metadata, symbols, fields, aliases
src/language/json.zig    string/number matchers
src/language/outline_scanner.zig newline/indent/dedent/blank scanning
src/input/*              chunked, reader, streaming, and UTF-16 sources
src/unicode/utf16.zig    BOM, surrogates, transcoding
src/debug/conformance.zig corpus-format parsing
...plus pure unit tests for core types, costs, logging, codecs, and arenas

Plus smoke tests at the bottom of src/treesitter.zig. Run everything with:

zig build test

Allocation-failure testing

The suite uses std.testing.failing_allocator to prove OutOfMemory propagates cleanly, and std.testing.allocator everywhere else so any leak fails the run:

var parser = treesitter.Parser.init(std.testing.failing_allocator);
defer parser.deinit();
try parser.setLanguage(treesitter.expression_language);
try std.testing.expectError(error.OutOfMemory, parser.parseString("1 + 2"));

Testing your integration

• Parse representative valid sources and assert !tree.hasError() plus key node types and ranges.
• Parse broken sources and assert hasError() with isError() / isMissing() where you surface diagnostics.
• Round-trip incremental edits and assert the result equals a fresh parse.
• Compile queries once in setup; assert matchCount() and capture texts.

Related pages

• Development: Testing, Troubleshooting