tests for help command, listing examples, and copying examples

Author: cadenmyers13

tests/test_cli.py

@@ -0,0 +1,39 @@
+import pytest
+
+from diffpy.cmi.cli import main
+
+
+def test_cli_help(capsys):
+    """Test that the CLI help message is displayed correctly."""
+    with pytest.raises(SystemExit) as exc:
+        main(["--help", "-h"])
+    assert exc.value.code == 0
+    out, _ = capsys.readouterr()
+    assert "Welcome to diffpy.cmi" in out
+
+
+def test_example_list(capsys):
+    """Test that the example listing works."""
+    rc = main(["example", "list"])
+    assert rc == 0
+    out, _ = capsys.readouterr()
+    # test specific known pack and example
+    assert "ch03NiModelling" in out
+    assert "pdf" in out
+
+
+def test_example_copy(monkeypatch, tmp_path):
+    """Test that an example can be copied to the current directory."""
+    # create a fake example
+    fake_examples = tmp_path / "docs" / "examples"
+    src = fake_examples / "pack1" / "ex1"
+    src.mkdir(parents=True)
+    monkeypatch.setattr(
+        "diffpy.cmi.cli._installed_examples_dir",
+        lambda: fake_examples,
+    )
+    cwd = tmp_path
+    monkeypatch.chdir(cwd)
+    rc = main(["example", "copy", "pdf/ch03NiModelling"])
+    assert rc == 0
+    assert (cwd / "ch03NiModelling").exists()