Add test_click.py

tests/test_click.py

@@ -0,0 +1,19 @@
+import pytest
+from backupill.cli import main
+from click.testing import CliRunner
+
+
+def test_nothing_found():
+    runner = CliRunner()
+    result = runner.invoke(main, [""])
+
+    assert result.exit_code == 0
+    assert "Usage: packupill FILENAME.asc" in result.output
+
+
+def test_nothing_file():
+    runner = CliRunner()
+    result = runner.invoke(main, ["FILENAME.asc"])
+
+    assert result.exit_code == 0
+    assert "Error: File 'FILENAME.asc' not found!" in result.output