Add a utility for finding test fixtures that allows it to not exist i…

com/win32comext/directsound/test/ds_test.py

@@ -5,7 +5,7 @@
 import pywintypes
 import win32event, win32api
 import os
-from pywin32_testutil import TestSkipped
+from pywin32_testutil import TestSkipped, find_test_fixture
 import win32com.directsound.directsound as ds
 import pythoncom
 
@@ -301,22 +301,12 @@ def testCreate(self):
 
     def testPlay(self):
         """Mesdames et Messieurs, la cour de Devin Dazzle"""
-        # look for the test file in various places
-        candidates = [
-            os.path.dirname(__file__),
-            os.path.dirname(sys.argv[0]),
-            # relative to 'testall.py' in the win32com test suite.
-            os.path.join(
-                os.path.dirname(sys.argv[0]), "../../win32comext/directsound/test"
-            ),
-            ".",
-        ]
-        for candidate in candidates:
-            fname = os.path.join(candidate, "01-Intro.wav")
-            if os.path.isfile(fname):
-                break
-        else:
-            raise TestSkipped("Can't find test .wav file to play")
+        # relative to 'testall.py' in the win32com test suite.
+        extra = os.path.join(
+            os.path.dirname(sys.argv[0]), "../../win32comext/directsound/test"
+        )
+
+        fname = find_test_fixture("01-Intro.wav", extra)
 
         with open(fname, "rb") as f:
             hdr = f.read(WAV_HEADER_SIZE)

win32/Lib/pywin32_testutil.py

@@ -1,5 +1,7 @@
 # Utilities for the pywin32 tests
+import site
 import sys
+import os
 import unittest
 import gc
 import winerror
@@ -193,6 +195,39 @@ def check_is_admin():
     return _is_admin
 
 
+# Find a test "fixture" (eg, binary test file) expected to be very close to
+# the test being run.
+# If the tests are being run from the "installed" version, then these fixtures
+# probably don't exist - the test is "skipped".
+# But it's fatal if we think we might be running from a pywin32 source tree.
+def find_test_fixture(basename, extra_dir="."):
+    # look for the test file in various places
+    candidates = [
+        os.path.dirname(sys.argv[0]),
+        extra_dir,
+        ".",
+    ]
+    for candidate in candidates:
+        fname = os.path.join(candidate, basename)
+        if os.path.isfile(fname):
+            return fname
+    else:
+        # Can't find it - see if this is expected or not.
+        # This module is typically always in the installed dir, so use argv[0]
+        this_file = os.path.normcase(os.path.abspath(sys.argv[0]))
+        dirs_to_check = site.getsitepackages()[:]
+        if site.USER_SITE:
+            dirs_to_check.append(site.USER_SITE)
+
+        for d in dirs_to_check:
+            d = os.path.normcase(d)
+            if os.path.commonprefix([this_file, d]) == d:
+                # looks like we are in an installed Python, so skip the text.
+                raise TestSkipped(f"Can't find test fixture '{fname}'")
+        # Looks like we are running from source, so this is fatal.
+        raise RuntimeError(f"Can't find test fixture '{fname}'")
+
+
 # If this exception is raised by a test, the test is reported as a 'skip'
 class TestSkipped(Exception):
     pass