Feature orphans (#755)

* Initial implementation of orphan command

* Implemented orphans command, #84

tests/test_cli_orphans.py

@@ -0,0 +1,35 @@
+"""Test `osxphotos orphan` CLI"""
+
+import os.path
+
+from click.testing import CliRunner
+
+from osxphotos.cli.orphans import orphans
+
+from .test_cli import PHOTOS_DB_15_7
+
+
+def test_orphans():
+    """test basic orphans"""
+    runner = CliRunner()
+    cwd = os.getcwd()
+    # pylint: disable=not-context-manager
+    with runner.isolated_filesystem():
+        result = runner.invoke(
+            orphans, ["--db", os.path.join(cwd, PHOTOS_DB_15_7), "-V"]
+        )
+        assert result.exit_code == 0
+        assert "Found 1 orphan" in result.output
+
+
+def test_orphans_export():
+    """test export of orphans"""
+    runner = CliRunner()
+    cwd = os.getcwd()
+    # pylint: disable=not-context-manager
+    with runner.isolated_filesystem():
+        result = runner.invoke(
+            orphans, ["--db", os.path.join(cwd, PHOTOS_DB_15_7), "--export", ".", "-V"]
+        )
+        assert result.exit_code == 0
+        assert "Exported 1 file" in result.output