tests: Add fuzz test

.gitignore

@@ -10,3 +10,6 @@ coverage.xml
 .mypy_cache
 /subprojects/gtk-blueprint-tool
 /blueprint-regression-tests
+
+/corpus
+/crashes

.gitlab-ci.yml

@@ -25,6 +25,20 @@ build:
     reports:
       cobertura: coverage.xml
 
+fuzz:
+  image: registry.gitlab.gnome.org/jwestman/blueprint-compiler
+  stage: build
+  allow_failure: true
+  script:
+    - meson _build
+    - ninja -C _build install
+    - ./tests/fuzz.sh 5000
+  artifacts:
+    when: always
+    paths:
+      - corpus
+      - crashes
+
 pages:
   stage: pages
   dependencies:

build-aux/Dockerfile

@@ -1,5 +1,9 @@
 FROM fedora:latest
 
-RUN dnf install -y meson python3-pip gtk4-devel gobject-introspection-devel libadwaita-devel
+RUN dnf install -y meson python3-pip gtk4-devel gobject-introspection-devel libadwaita-devel python3-devel
 RUN pip3 install furo mypy sphinx coverage
+
+# The version on PyPI is very old and doesn't install. Use the upstream package registry instead.
+RUN pip install pythonfuzz --extra-index-url https://gitlab.com/api/v4/projects/19904939/packages/pypi/simple
+
 RUN dnf install -y git

tests/fuzz.py

@@ -0,0 +1,27 @@
+from pythonfuzz.main import PythonFuzz
+
+from blueprintcompiler import tokenizer, parser, decompiler
+from blueprintcompiler.completions import complete
+from blueprintcompiler.errors import PrintableError, MultipleErrors, CompileError, CompilerBugError
+from blueprintcompiler.tokenizer import Token, TokenType, tokenize
+from blueprintcompiler import utils
+
+@PythonFuzz
+def fuzz(buf):
+    try:
+        blueprint = buf.decode("ascii")
+
+        tokens = tokenizer.tokenize(blueprint)
+        ast, errors, warnings = parser.parse(tokens)
+
+        if errors is None and len(ast.errors) == 0:
+            actual = ast.generate()
+    except CompilerBugError as e:
+        raise e
+    except PrintableError:
+        pass
+    except UnicodeDecodeError:
+        pass
+
+if __name__ == "__main__":
+    fuzz()

tests/fuzz.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+if [ $# = 1 ]; then
+  RUNS="$1"
+else
+  RUNS=-1
+fi
+
+mkdir -p corpus
+cp tests/samples/*.blp corpus
+cp tests/sample_errors/*.blp corpus
+python3 tests/fuzz.py --runs $RUNS corpus