Tests

• internal/wlgen tests the generated signatures and checks, then builds a registry client from the vendored protocols and, when a Wayland compositor is running, runs it.

• internal/vkgen tests declaration parsing, extension enum values and the selection format, checks the shape of the generated bindings, and renders a rounded, bordered quad offscreen with the quad shaders through the bindings and dynamic rendering, comparing pixels. It skips without libvulkan or a Vulkan 1.3 device.

• internal/shaders checks that the SPIR-V matches the recorded source sums and validates it with spirv-val when installed.

• internal/hot tests reload against running programs:

  • state kept across a code swap;
  • functions added;
  • compile errors leaving the program running;
  • heap data surviving a reload while the collector runs;
  • stored function values, closures and callbacks running patched code;
  • instances of an edited generic function patched;
  • restarts on layout, signature and capture changes.

• cmd/low compiles each of these twice in one process and requires identical SSA form and assembly:

  • each benchmark, for release, dev and Windows;
  • every testdata/run program except the std_ ones, for release;
  • std_otel_export, for release, dev and Windows;
  • every testdata/windows program, for Windows.

• cmd/lowfuzz generates well-typed, terminating programs from a choice stream (internal/fuzz/gen), predicts their output with a reference interpreter (internal/fuzz/model), compiles each for release and dev, runs both, and reports any of these (internal/fuzz/oracle):

  • compiler panic;
  • rejected program;
  • link failure;
  • timeout;
  • release/dev difference;
  • difference from the prediction.

  The generator covers every integer width, f32 and f64, shifts, conversions, if expressions, functions, and for loops with labelled break and continue. Float values are observed through clamped integer conversions and NaN comparisons.

• internal/fuzz/reduce minimises each new signature. It removes functions, parameters and statements, unwraps if and loop bodies, replaces expressions with literals or their operands, and shrinks literals, keeping only candidates that still produce the signature. -reduce-tests bounds the compiler runs.

  • The minimised program is saved under -out, one per distinct signature.
  • With -fixtures it is also written there as a testdata/run fixture (.low with the predicted .out and .err, named by content hash) that fails until the bug is fixed.

• go test ./... also compiles every testdata/run/*.low and every program directory in testdata/run, runs it with a one-minute limit, compares stdout with .out and stderr with .err, and checks peak memory against .maxrss in KB when present.

  • A program with a .needed file must link exactly those shared libraries. Every other program must be static with no interpreter.
  • Each testdata/fail/*.low file or directory must fail to compile with the message in its .err, with file paths shown relative to the fixture.