testing: Enable automatic selection of the OS image based on the test…

… and filename prefix, addressing an issue in the development environment.

For example, when using VSCode with pytest, test autodiscovery triggers pytest_generate_tests(), adding all images to each test case. This causes issues, as Linux tests end up being executed with Windows and Mac images, and vice versa.

.github/workflows/test.yaml

@@ -25,10 +25,13 @@ jobs:
 
     - name: Download images
       run: |
+        mkdir test_images
+        cd test_images
         curl -sLO "https://downloads.volatilityfoundation.org/volatility3/images/linux-sample-1.bin.gz"
         gunzip linux-sample-1.bin.gz
         curl -sLO "https://downloads.volatilityfoundation.org/volatility3/images/win-xp-laptop-2005-06-25.img.gz"
         gunzip win-xp-laptop-2005-06-25.img.gz
+        cd -
 
     - name: Download and Extract symbols
       run: |
@@ -39,13 +42,12 @@ jobs:
 
     - name: Testing...
       run: |
-        pytest ./test/test_volatility.py --volatility=vol.py --image win-xp-laptop-2005-06-25.img -k test_windows -v
-        pytest ./test/test_volatility.py --volatility=vol.py --image linux-sample-1.bin -k test_linux -v
+        pytest ./test/test_volatility.py --volatility=vol.py --image-dir=./test_images -k test_windows -v
+        pytest ./test/test_volatility.py --volatility=vol.py --image-dir=./test_images -k test_linux -v
 
     - name: Clean up post-test
       run: |
-        rm -rf *.bin
-        rm -rf *.img
+        rm -rf test_images
         cd volatility3/symbols
         rm -rf linux
         rm -rf linux.zip

test/conftest.py

@@ -35,16 +35,39 @@ def pytest_addoption(parser):
 def pytest_generate_tests(metafunc):
     """Parameterize tests based on image names"""
 
-    images = metafunc.config.getoption("image")
+    images = metafunc.config.getoption("image").copy()
     for image_dir in metafunc.config.getoption("image_dir"):
-        images = images + [
-            os.path.join(image_dir, dir) for dir in os.listdir(image_dir)
+        images += [
+            os.path.join(image_dir, dir_name) for dir_name in os.listdir(image_dir)
         ]
 
-    # tests with "image" parameter are run against images
+    # tests with "image" parameter are run against image
     if "image" in metafunc.fixturenames:
+        filtered_images = []
+        ids = []
+        for image in images:
+            image_base = os.path.basename(image)
+            test_name = metafunc.definition.originalname
+            if test_name.startswith("test_windows_") and not image_base.startswith(
+                "win-"
+            ):
+                continue
+            elif test_name.startswith("test_linux_") and not image_base.startswith(
+                "linux-"
+            ):
+                continue
+            elif test_name.startswith("test_mac_") and not image_base.startswith(
+                "mac-"
+            ):
+                continue
+
+            filtered_images.append(image)
+            ids.append(image_base)
+
         metafunc.parametrize(
-            "image", images, ids=[os.path.basename(image) for image in images]
+            "image",
+            filtered_images,
+            ids=ids,
         )