diff --git a/.gitignore b/.gitignore
index d43ea55..882a904 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 src/__pycache__/
+tests/__pycache__/
 _build/
+.hypothesis/
diff --git a/Makefile b/Makefile
index 66e57db..64921d5 100644
--- a/Makefile
+++ b/Makefile
@@ -14,11 +14,14 @@
 	test ! -d _build || rm -r _build
 
 tidy: _build/.stamp_venv
-	source _build/venv/bin/activate && black src
+	source _build/venv/bin/activate && black src tests
 
 grip: _build/.stamp_venv
 	source _build/venv/bin/activate && grip
 
+test: _build/.stamp_venv
+	source _build/venv/bin/activate && pytest --timeout=30 --timeout_method=thread
+
 venv_bash: _build/.stamp_venv
 	source _build/venv/bin/activate && bash
 _build:
diff --git a/requirements.txt b/requirements.txt
index 2f33ed0..f6600ad 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,5 @@
 black
 grip
+pytest
+pytest-timeout
+hypothesis
diff --git a/src/interp.py b/src/interp.py
index 08585f3..2f0c8a5 100644
--- a/src/interp.py
+++ b/src/interp.py
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 # Copyright 2021 Jookia <contact@jookia.org>
 
-import ast_types
+from src import ast_types
 import sys
 
 
diff --git a/src/main.py b/src/main.py
index f3eaea3..cb0e0c7 100755
--- a/src/main.py
+++ b/src/main.py
@@ -2,9 +2,9 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 # Copyright 2021 Jookia <contact@jookia.org>
 
-import log
-import parse
-import interp
+from src import log
+from src import parse
+from src import interp
 import sys
 
 
diff --git a/src/parse.py b/src/parse.py
index e031faa..1af5010 100644
--- a/src/parse.py
+++ b/src/parse.py
@@ -1,8 +1,8 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 # Copyright 2021 Jookia <contact@jookia.org>
 
-import log
-import ast_types
+from src import log
+from src import ast_types
 
 
 class ParseLocation:
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..37db15a
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+# Dummy file to help pytest find the src module
diff --git a/tests/test_parse.py b/tests/test_parse.py
new file mode 100644
index 0000000..22e1588
--- /dev/null
+++ b/tests/test_parse.py
@@ -0,0 +1,15 @@
+from hypothesis import given
+from hypothesis.strategies import binary
+
+from src import parse
+
+
+@given(binary(), binary())
+def test_parser_fuzz(code, filename):
+    try:
+        tokenizer = parse.Tokenizer(code, filename)
+        tokens = tokenizer.tokenize()
+        parser = parse.Parser(tokens)
+        parser.parse_file()
+    except parse.ParseError:
+        pass