Test unit returned as a separate command

tests/test_x2pdf.py

@@ -28,4 +28,44 @@ def test_x2pdf(capsys, tmp_path: Path) -> None:
     captured = capsys.readouterr()
     assert exit_code == 0, captured
     assert captured.out == ""
-    assert output.exists()
+    assert output.exists()
+
+def test_x2pdf_with_format(capsys, tmp_path: Path) -> None:
+    # Arrange
+    output = tmp_path / "out.pdf"
+    assert not output.exists()
+
+    formats_to_test = [
+        "Letter",
+        "A4-portrait",
+        "A4-landscape",
+        "210x297",
+        "invalid-format"
+    ]
+
+    for format_option in formats_to_test:
+        # Act
+        exit_code = run_cli(
+            [
+                "x2pdf",
+                "sample-files/003-pdflatex-image/page-0-Im1.jpg",
+                "--output",
+                str(output),
+                "--format",
+                format_option,
+            ]
+        )
+
+        # Assert
+        captured = capsys.readouterr()
+
+        # For valid formats, we expect a successful exit code and the output file to exist
+        if format_option != "invalid-format":
+            assert exit_code == 0, captured
+            assert captured.out == ""
+            assert output.exists()
+        else:
+            # For an invalid format, we expect a non-zero exit code (indicating failure)
+            assert exit_code != 0
+            assert "Invalid format" in captured.err  # Check for expected error message
+        output.unlink(missing_ok=True)  # Clean up for the next test iteration