Use explicit per-test filenames in save tests

Replace the module-level `filename_gen` counter in test_ggsave.py and
test_save_as_pdf_pages.py with explicit, test-specific filenames. The
shared generator caused random failures under `pytest -n auto`: each
xdist worker reset its counter to zero, so workers raced on the same
`filename-N.png` paths in CWD. Naming each file after the test that
writes it makes basenames unique within a module, and matching the
extension to the actual format (.pdf in test_save_as_pdf_pages.py)
removes the cross-module collision on `test_save_method`.

Author: has2k1

tests/test_ggsave.py

@@ -21,18 +21,10 @@
 p = ggplot(mtcars, aes(x="wt", y="mpg", label="name")) + geom_text()
 
 
-def sequential_filenames():
-    """
-    Generate filenames for the tests
-    """
-    for i in range(100):
-        yield Path(f"filename-{i}.png")
-
-
-filename_gen = sequential_filenames()
-
-
 def assert_exist_and_clean(filename, msg=None):
+    if isinstance(filename, str):
+        filename = Path(filename)
+
     if not msg:
         msg = f"File {filename} does not exist"
     assert filename.exists(), msg
@@ -46,27 +38,26 @@ def test_default_filename(self):
         assert_exist_and_clean(fn, "default filename")
 
     def test_save_method(self):
-        fn = next(filename_gen)
+        fn1 = "save_method-01.png"
         with pytest.warns(PlotnineWarning) as record:
-            p.save(fn)
+            p.save(fn1)
 
-        assert_exist_and_clean(fn, "save method")
+        assert_exist_and_clean(fn1, "save method")
 
         res = ("saving" in str(item.message).lower() for item in record)
         assert any(res)
 
         res = ("filename" in str(item.message).lower() for item in record)
         assert any(res)
 
-        # verbose
-        fn = next(filename_gen)
+        fn2 = "save_method-02.png"
         with warnings.catch_warnings(record=True) as record:
-            p.save(fn, verbose=False)
-            assert_exist_and_clean(fn, "save method")
+            p.save(fn2, verbose=False)
+            assert_exist_and_clean(fn2, "save method")
             assert not record, "Issued an unexpected warning"
 
     def test_filename_plot_path(self):
-        fn = next(filename_gen)
+        fn = "filename_plot_path.png"
         p.save(fn, path=".", verbose=False)
         assert_exist_and_clean(fn, "fn, plot and path")
 
@@ -76,7 +67,7 @@ def test_format_png(self):
         assert_exist_and_clean(fn, "format png")
 
     def test_dpi(self):
-        fn = next(filename_gen)
+        fn = "dpi.png"
         p.save(fn, dpi=100, verbose=False)
         assert_exist_and_clean(fn, "dpi = 100")
 
@@ -86,24 +77,21 @@ def test_ggsave(self):
         assert_exist_and_clean(fn, "default filename")
 
     def test_save_big(self):
-        fn = next(filename_gen)
         # supplying the ggplot object will work without
         # printing it first! 26 is the current limit, just go
         # over it to not use too much memory
-        p.save(fn, width=26, height=26, limitsize=False, verbose=False)
-        assert_exist_and_clean(fn, "big height and width")
+        fn1 = "save_big-01.png"
+        p.save(fn1, width=26, height=26, limitsize=False, verbose=False)
+        assert_exist_and_clean(fn1, "big height and width")
 
         # Using the global option
-        fn = next(filename_gen)
+        fn2 = "save_big-02.png"
         set_option("limitsize", False)
-        p.save(fn, width=26, height=26, verbose=False)
+        p.save(fn2, width=26, height=26, verbose=False)
         set_option("limitsize", True)
-        assert_exist_and_clean(fn, "big height and width")
+        assert_exist_and_clean(fn2, "big height and width")
 
     def test_dpi_theme_xkcd(self):
-        fn1 = next(filename_gen)
-        fn2 = next(filename_gen)
-
         data = pd.DataFrame({"x": range(4), "y": range(4), "b": list("aabb")})
 
         p = (
@@ -112,9 +100,11 @@ def test_dpi_theme_xkcd(self):
             + facet_wrap("b")
             + theme_xkcd()
         )
+        fn1 = "dpi_theme_xkcd-01.png"
         p.save(fn1, verbose=False)
         assert_exist_and_clean(fn1, "Saving with theme_xkcd and dpi (1)")
 
+        fn2 = "dpi_theme_xkcd-02.png"
         p.save(fn2, dpi=72, verbose=False)
         assert_exist_and_clean(fn2, "Saving with theme_xkcd and dpi (2)")
 
@@ -149,7 +139,7 @@ def test_bad_units(self):
 # "leakages" due to the tests in this test module.
 def test_ggsave_closes_plot():
     assert plt.get_fignums() == [], "There are unsaved test plots"
-    fn = next(filename_gen)
+    fn = "ggsave_closes_plot.png"
     p.save(fn, verbose=False)
     assert_exist_and_clean(fn, "exist")
     assert plt.get_fignums() == [], "ggplot.save did not close the plot"

tests/test_save_as_pdf_pages.py

@@ -17,18 +17,10 @@ def p(N=3):
         yield template + ggtitle("%d of %d" % (i, N))
 
 
-def sequential_filenames():
-    """
-    Generate filenames for the tests
-    """
-    for i in range(100):
-        yield Path(f"filename-{i}.png")
-
-
-filename_gen = sequential_filenames()
-
-
 def assert_exist_and_clean(filename, msg=None):
+    if isinstance(filename, str):
+        filename = Path(filename)
+
     if not msg:
         msg = f"File {filename} does not exist"
     assert filename.exists(), msg
@@ -42,8 +34,8 @@ def test_default_filename(self):
         fn = plots[0]._save_filename("pdf")
         assert_exist_and_clean(fn, "default filename")
 
-    def test_save_method(self):
-        fn = next(filename_gen)
+    def test_save_as_pdf_method(self):
+        fn = "save_as_pdf_method-01.pdf"
         with pytest.warns(UserWarning) as record:
             save_as_pdf_pages(p(), fn)
 
@@ -53,7 +45,7 @@ def test_save_method(self):
         assert any(res)
 
         # verbose
-        fn = next(filename_gen)
+        fn = "save_as_pdf_method-02.pdf"
         with warnings.catch_warnings(record=True) as record:
             save_as_pdf_pages(p(), fn, verbose=False)
             assert_exist_and_clean(fn, "save method")
@@ -63,7 +55,7 @@ def test_save_method(self):
         assert not any(res)
 
     def test_filename_plot_path(self):
-        fn = next(filename_gen)
+        fn = "filename_plot_path.pdf"
         with pytest.warns(PlotnineWarning):
             save_as_pdf_pages(p(), fn, path=".")
         assert_exist_and_clean(fn, "fn, plot and path")
@@ -76,7 +68,7 @@ def test_height_width(self):
         plots = []
         for i, plot in enumerate(p()):
             plots.append(plot + theme(figure_size=(8 + i, 6 + i)))
-        fn = next(filename_gen)
+        fn = "height_width.pdf"
         with pytest.warns(PlotnineWarning):
             save_as_pdf_pages(plots, fn)
         # assert False, "Check %s" % fn  # Uncomment to check
@@ -85,24 +77,25 @@ def test_height_width(self):
 class TestExceptions:
     def test_plot_exception(self):
         # Force an error in drawing
-        fn = next(filename_gen)
+        fn = "plot_exception.pdf"
         plots = list(p())
         plots[0] += aes(color="unknown")
         with pytest.raises(PlotnineError):
             save_as_pdf_pages(plots, fn, verbose=False)
 
+        fn_path = Path(fn)
         # TODO: Remove when MPL>=3.10.0
-        if fn.exists():
-            fn.unlink()
+        if fn_path.exists():
+            fn_path.unlink()
 
-        assert not fn.exists()
+        assert not fn_path.exists()
 
 
 # This should be the last function in the file since it can catch
 # "leakages" due to the tests in this test module.
 def test_save_as_pdf_pages_closes_plots():
     assert plt.get_fignums() == [], "There are unsaved test plots"
-    fn = next(filename_gen)
+    fn = "save_as_pdf_pages_closes_plots.pdf"
     with pytest.warns(PlotnineWarning):
         save_as_pdf_pages(p(), fn)
     assert_exist_and_clean(fn, "exist")