Add option to use different reference arrays for derived test classes

pytest_arraydiff/plugin.py

@@ -309,9 +309,16 @@ def pytest_runtest_call(self, item):
 
         # Find test name to use as plot name
         filename = compare.kwargs.get('filename', None)
+        derive_classes = compare.kwargs.get('derive_classes', False)
         if filename is None:
             if single_reference:
                 filename = item.originalname + '.' + extension
+            elif derive_classes:
+                filename = test_name
+                filename = filename.replace('.', '_')
+                filename = filename + '.' + extension
+                filename = filename.replace('[', '_').replace(']', '_')
+                filename = filename.replace('_.' + extension, '.' + extension)
             else:
                 filename = item.name + '.' + extension
                 filename = filename.replace('[', '_').replace(']', '_')

tests/baseline/test_pytest_arraydiff_TestDerivedOne_test_array_one.txt

@@ -0,0 +1,3 @@
+0 1 2 3
+4 5 6 7
+8 9 10 11

tests/baseline/test_pytest_arraydiff_TestDerivedTwo_test_array_one.txt

@@ -0,0 +1,2 @@
+0 1 2 3 4
+5 6 7 8 9

tests/test_pytest_arraydiff.py

@@ -176,3 +176,54 @@ def test_single_reference(self, spam):
 
 def test_nofile():
     pass
+
+class BaseTestClass:
+    arrays = None
+    @pytest.mark.array_compare(reference_dir=reference_dir, file_format='text', derive_classes=True)
+    def test_array_one(self):
+        return self.array
+class TestDerivedOne(BaseTestClass):
+    array = np.arange(3 * 4).reshape((3, 4))
+
+class TestDerivedTwo(BaseTestClass):
+    array = np.arange(2 * 5).reshape((2, 5))
+
+
+
+DERIVED_FAILING = """
+import pytest
+import numpy as np
+class BaseTestClass:
+    arrays = None
+    @pytest.mark.array_compare(reference_dir="{reference_dir}", file_format='text')
+    def test_array_one(self):
+        return self.array
+class TestDerivedOne(BaseTestClass):
+    array = np.arange(3 * 4).reshape((3, 4))
+
+class TestDerivedTwo(BaseTestClass):
+    array = np.arange(2 * 5).reshape((2, 5))
+"""
+
+
+def test_derived_fails():
+
+    tmpdir = tempfile.mkdtemp()
+
+    test_file = os.path.join(tmpdir, 'test.py')
+    gen_dir = os.path.join(tmpdir, 'spam', 'egg')
+    with open(test_file, 'w') as f:
+        f.write(DERIVED_FAILING.format(reference_dir=gen_dir))
+
+    # If we use --arraydiff, it should detect that the file is missing
+    code = subprocess.call(f'pytest --arraydiff {test_file}', shell=True)
+    assert code != 0
+
+    # when we generate the test files without the derive option the generation should succeed
+    code = subprocess.call(['pytest', f'--arraydiff-generate-path={gen_dir}', test_file],
+                           timeout=10)
+    assert code == 0
+
+    # but when the test is run again, it should fail, because the different tests are looking at the same file
+    code = subprocess.call(f'pytest --arraydiff {test_file}', shell=True)
+    assert code != 0