fix cli bug + add cli tests

tests/test_cli.py

+"""Test CLI."""
+
+from click.testing import CliRunner
+from theia_dumper.cli import list_cols, list_col_items, grab, collection_diff
+
+
+def _test_cli(command, args=None):
+    """Test a CLI command."""
+    print(f"Testing {command}")
+    runner = CliRunner()
+    result = runner.invoke(command, args)
+    print(result)
+    assert result.exit_code == 0
+
+
+_test_cli(list_cols)
+_test_cli(list_col_items, ["--col_id", "spot-6-7-drs"])
+_test_cli(grab, ["--col_id", "spot-6-7-drs", "--out_json", "/tmp/col.json"])
+_test_cli(grab, ["--col_id", "spot-6-7-drs", "--out_json", "/tmp/col.json", "--pretty"])
+_test_cli(
+    grab,
+    [
+        "--col_id",
+        "spot-6-7-drs",
+        "--item_id",
+        "SPOT7_MS_201805051026429_SPOT7_P_201805051026429_1",
+        "--out_json",
+        "/tmp/item.json",
+    ],
+)
+_test_cli(
+    grab,
+    [
+        "--col_id",
+        "spot-6-7-drs",
+        "--item_id",
+        "SPOT7_MS_201805051026429_SPOT7_P_201805051026429_1",
+        "--out_json",
+        "/tmp/item.json",
+        "--pretty",
+    ],
+)
+_test_cli(
+    collection_diff, ["--remote_id", "spot-6-7-drs", "--col_path", "/tmp/col.json"]
+)