feat: Check scanline is available

scanline_wrapper.py

@@ -84,8 +84,20 @@ def _get_scanline_cmd():
     return os.environ.get("SCANLINE_CMD", "scanline")
 
 
-def _check_scanline_available():
-    raise NotImplementedError()  # TODO
+def _is_scanline_available():
+    """Checks if the scanline command is available.
+
+    :rtype: bool
+    """
+    cmd = _get_scanline_cmd()
+    if os.path.isfile(cmd) and os.access(cmd, os.X_OK):
+        return True
+    if "PATH" in os.environ:
+        for path in os.environ["PATH"].split(":"):
+            cmd_path = os.path.join(path, cmd)
+            if os.path.isfile(cmd_path) and os.access(cmd_path, os.X_OK):
+                return True
+    return False
 
 
 def list_scanners(browsesecs=1, verbose=False):
@@ -102,6 +114,11 @@ def list_scanners(browsesecs=1, verbose=False):
     :rtype: list(str)
     :returns: the available scanners.
     """
+    if not _is_scanline_available():
+        raise ScanlineExecutableNotFound(
+            "The scanline command was not found. Is scanline installed?"
+        )
+
     command = [_get_scanline_cmd()]
     command += ["-list"]
     command += ["-browsesecs", str(browsesecs)]
@@ -167,6 +184,11 @@ def scan_flatbed(
 
     :rtype: None
     """
+    if not _is_scanline_available():
+        raise ScanlineExecutableNotFound(
+            "The scanline command was not found. Is scanline installed?"
+        )
+
     # Normalize path
     output_path = Path(output_path).absolute()
 

test/test_wrapper.py

@@ -16,6 +16,28 @@ def test_env_overide(self, monkeypatch):
         assert scanline_wrapper._get_scanline_cmd() == "foobar"
 
 
+class Test__is_scanline_available:
+
+    def test_with_command_not_available(self, monkeypatch):
+        monkeypatch.setenv(
+            "SCANLINE_CMD",
+            (Path(__file__).parent / "mock" / "scanline-not-exists").as_posix(),
+        )
+        assert scanline_wrapper._is_scanline_available() is False
+
+    def test_with_command_path(self, monkeypatch):
+        monkeypatch.setenv(
+            "SCANLINE_CMD",
+            (Path(__file__).parent / "mock" / "scanline-nop.sh").as_posix(),
+        )
+        assert scanline_wrapper._is_scanline_available() is True
+
+    def test_with_command_in_path(self, monkeypatch):
+        monkeypatch.setenv("PATH", (Path(__file__).parent / "mock").as_posix())
+        monkeypatch.setenv("SCANLINE_CMD", "scanline-nop.sh")
+        assert scanline_wrapper._is_scanline_available() is True
+
+
 class Test_list_scanner:
 
     def test_list_scanner_with_2_scanners(self, monkeypatch):
@@ -36,6 +58,14 @@ def test_list_scanner_with_no_scanners(self, monkeypatch):
         scanners = scanline_wrapper.list_scanners()
         assert len(scanners) == 0
 
+    def test_scanline_not_available(self, monkeypatch):
+        monkeypatch.setenv(
+            "SCANLINE_CMD",
+            (Path(__file__).parent / "mock" / "scanline-not-exists").as_posix(),
+        )
+        with pytest.raises(scanline_wrapper.ScanlineExecutableNotFound):
+            scanline_wrapper.list_scanners()
+
 
 class Test_scan_flatbed:
 
@@ -126,3 +156,11 @@ def test_scanner_not_found(self, monkeypatch, tmp_path):
 
         with pytest.raises(scanline_wrapper.ScanlineScannerNotFound):
             scanline_wrapper.scan_flatbed(tmp_path / "out.jpg", scanner="XXXXXXXX")
+
+    def test_scanline_not_available(self, monkeypatch, tmp_path):
+        monkeypatch.setenv(
+            "SCANLINE_CMD",
+            (Path(__file__).parent / "mock" / "scanline-not-exists").as_posix(),
+        )
+        with pytest.raises(scanline_wrapper.ScanlineExecutableNotFound):
+            scanline_wrapper.scan_flatbed(tmp_path / "out.jpg")