Add tests for cli

Author: rhpvorderman

src/isal/igzip.py

@@ -296,8 +296,7 @@ def main():
         else:
             base, extension = os.path.splitext(args.file)
             if extension != ".gz":
-                print(f"filename doesn't end in .gz: {args.file}")
-                return
+                raise ValueError(f"filename doesn't end in .gz: {args.file}")
             in_file = open(args.file, "rb")
             out_file = io.open(base, "wb")
     try:

tests/test_gzip_compliance.py

@@ -816,11 +816,17 @@ def test_decompress_infile_outfile(self):
         self.assertTrue(os.path.exists(igzipname))
 
     def test_decompress_infile_outfile_error(self):
-        rc, out, err = assert_python_ok('-m', 'isal.igzip', '-d',
-                                        'thisisatest.out')
-        self.assertIn(b"filename doesn't end in .gz:", out)
-        self.assertEqual(rc, 0)
-        self.assertEqual(err, b'')
+        rc, out, err = assert_python_failure('-m', 'isal.igzip', '-d',
+                                             'thisisatest.out')
+        # We take a divide from the original gzip module here. Error messages
+        # should be printed in stderr. Also exit code should not be 0!
+        # in python -m gzip -d mycompressedfile > decompressed
+        # will simply make decompressed contents 'filename doesn't end in .gz'
+        # without throwing an error. Crazy!
+        # TODO: Report a bug in CPython for gzip module
+        self.assertIn(b"filename doesn't end in .gz:", err)
+        self.assertNotEqual(rc, 0)
+        self.assertEqual(out, b'')
 
     @create_and_remove_directory(TEMPDIR)
     def test_compress_stdin_outfile(self):

tests/test_igzip_cli.py

@@ -18,6 +18,10 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
+"""Tests for the igzip CLI. Uses pytest which works better than unittest for
+these sort of tests. Meant to complement the gzip module compliance tests.
+It should improve coverage as well."""
+
 import gzip
 import io
 import sys
@@ -39,6 +43,7 @@ def test_decompress_stdin_stdout(capsysbinary, level):
     sys.argv = ["", "-d"]
     igzip.main()
     out, err = capsysbinary.readouterr()
+    assert err == b''
     assert out == DATA
 
 
@@ -49,21 +54,40 @@ def test_compress_stdin_stdout(capsysbinary, level):
     sys.argv = ["", f"-{level}"]
     igzip.main()
     out, err = capsysbinary.readouterr()
+    assert err == b''
     assert gzip.decompress(out) == DATA
 
 
-def test_decompress_infile_outfile(tmp_path):
+def test_decompress_infile_outfile(tmp_path, capsysbinary):
     test_file = tmp_path / "test"
     compressed_temp = test_file.with_suffix(".gz")
     compressed_temp.write_bytes(gzip.compress(DATA))
     sys.argv = ['', '-d', str(compressed_temp)]
     igzip.main()
+    out, err = capsysbinary.readouterr()
+    assert err == b''
+    assert out == b''
+    assert test_file.exists()
     assert test_file.read_bytes() == DATA
 
 
-def test_compress_infile_outfile(tmp_path):
+def test_compress_infile_outfile(tmp_path, capsysbinary):
     test_file = tmp_path / "test"
     test_file.write_bytes(DATA)
     sys.argv = ['', str(test_file)]
     igzip.main()
-    assert gzip.decompress(test_file.with_suffix(".gz").read_bytes()) == DATA
+    out_file = test_file.with_suffix(".gz")
+    out, err = capsysbinary.readouterr()
+    assert err == b''
+    assert out == b''
+    assert out_file.exists()
+    assert gzip.decompress(out_file.read_bytes()) == DATA
+
+
+def test_decompress_infile_outfile_error(capsysbinary):
+    sys.argv = ['', '-d', 'thisisatest.out']
+    with pytest.raises(ValueError) as error:
+        igzip.main()
+    assert error.match("filename doesn't end")
+    out, err = capsysbinary.readouterr()
+    assert out == b''