Skip lz4 tests only if neither the bindings nor the lz4 binary are installed

Author: marcelm

tests/test_xopen.py

@@ -32,9 +32,11 @@
 TEST_DIR = Path(__file__).parent
 CONTENT_LINES = ["Testing, testing ...\n", "The second line.\n"]
 CONTENT = "".join(CONTENT_LINES)
-extensions = ["", ".gz", ".bz2", ".xz", ".lz4"]
+extensions = ["", ".gz", ".bz2", ".xz"]
 if shutil.which("zstd") or zstandard:
     extensions += [".zst"]
+if shutil.which("lz4") or lz4:
+    extensions += [".lz4"]
 base = os.path.join(os.path.dirname(__file__), "file.txt")
 files = [base + ext for ext in extensions]
 
@@ -113,8 +115,6 @@ def test_binary(fname):
 def test_roundtrip(ext, tmp_path, threads, mode):
     if ext == ".zst" and threads == 0 and zstandard is None:
         return
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     path = tmp_path / f"file{ext}"
     data = b"Hello" if mode == "b" else "Hello"
     with xopen(path, "w" + mode, threads=threads) as f:
@@ -209,8 +209,6 @@ def test_next(fname):
 
 
 def test_has_iter_method(ext, tmp_path):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     path = tmp_path / f"out{ext}"
     with xopen(path, mode="w") as f:
         # Writing anything isn’t strictly necessary, but if we don’t, then
@@ -278,8 +276,6 @@ def test_invalid_compression_level(tmp_path):
 def test_append(ext, threads, tmp_path):
     if ext == ".zst" and zstandard is None and threads == 0:
         pytest.skip("No zstandard installed")
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     text = b"AB"
     reference = text + text
     path = tmp_path / f"the-file{ext}"
@@ -296,8 +292,6 @@ def test_append(ext, threads, tmp_path):
 
 @pytest.mark.parametrize("ext", extensions)
 def test_append_text(ext, tmp_path):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     text = "AB"
     reference = text + text
     path = tmp_path / f"the-file{ext}"
@@ -391,8 +385,6 @@ def test_read_no_threads(ext):
 
 
 def test_write_threads(tmp_path, ext):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     path = tmp_path / f"out.{ext}"
     with xopen(path, mode="w", threads=3) as f:
         f.write("hello")
@@ -420,7 +412,6 @@ def test_write_no_threads(tmp_path, ext):
         # we fall back to an external process even when threads=0
         return
     if ext == ".lz4" and lz4 is None:
-        # Skip lz4 if lz4 is not installed
         return
     if ext == ".lz4" and lz4.frame is not None:
         klasses[".lz4"] = lz4.frame.LZ4FrameFile
@@ -473,8 +464,6 @@ def test_read_pathlib_binary(fname):
 
 
 def test_write_pathlib(ext, tmp_path):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     path = tmp_path / f"hello.txt{ext}"
     with xopen(path, mode="wt") as f:
         f.write("hello")
@@ -483,8 +472,6 @@ def test_write_pathlib(ext, tmp_path):
 
 
 def test_write_pathlib_binary(ext, tmp_path):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     path = tmp_path / f"hello.txt{ext}"
     with xopen(path, mode="wb") as f:
         f.write(b"hello")
@@ -522,8 +509,6 @@ def test_falls_back_to_lzma_open(lacking_xz_permissions):
 
 
 def test_open_many_writers(tmp_path, ext):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     files = []
     # Because lzma.open allocates a lot of memory,
     # open fewer files to avoid MemoryError on 32-bit architectures
@@ -569,8 +554,6 @@ def test_override_output_format_wrong_format(tmp_path):
 @pytest.mark.parametrize("opener", OPENERS)
 @pytest.mark.parametrize("extension", extensions)
 def test_text_encoding_newline_passthrough(opener, extension, tmp_path):
-    if extension == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     if extension == ".zst" and zstandard is None:
         return
     # "Eén ree\nTwee reeën\n" latin-1 encoded with \r for as line separator.
@@ -586,8 +569,6 @@ def test_text_encoding_newline_passthrough(opener, extension, tmp_path):
 @pytest.mark.parametrize("opener", OPENERS)
 @pytest.mark.parametrize("extension", extensions)
 def test_text_encoding_errors(opener, extension, tmp_path):
-    if extension == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     if extension == ".zst" and zstandard is None:
         return
     # "Eén ree\nTwee reeën\n" latin-1 encoded. This is not valid ascii.
@@ -727,8 +708,6 @@ def test_xopen_read_from_pipe(ext, threads):
 
 @pytest.mark.parametrize("threads", (0, 1))
 def test_xopen_write_to_pipe(threads, ext):
-    if ext == ".lz4" and shutil.which("lz4") is None:
-        pytest.skip("lz4 not installed")
     if ext == ".zst" and zstandard is None:
         return
     format = ext.lstrip(".")