Add command-line interface tests

losser/losser.py

@@ -228,12 +228,10 @@ def _process_dict(pattern_path, dict_, case_sensitive=False, **kwargs):
     return result
 
 
-def main(args=None):
-    # This should:
-    # - Read input data from stdin (JSON, also support CSV?)
-    # - Print output data to stdout (CSV, JSON lines)
-    # - Print errors and diagnostics to stderr, not stdout
-    # - Exit with meaningful exit status
+def main(args=None, table_function=None):
+
+    if table_function is None:
+        table_function = table
 
     # Parse the command-line arguments.
     parser = argparse.ArgumentParser(
@@ -260,7 +258,7 @@ def main(args=None):
 
     dicts = json.loads(input_data)
 
-    csv_string = table(dicts, parsed_args.columns, csv=True)
+    csv_string = table_function(dicts, parsed_args.columns, csv=True)
     sys.stdout.write(csv_string)
 
 

losser/test_cli.py

@@ -0,0 +1,99 @@
+"""Tests for the command-line argument parsing."""
+import mock
+import losser
+import os
+import os.path
+import StringIO
+import inspect
+
+
+devnull = open(os.devnull, 'w')
+
+
+@mock.patch('sys.stderr', devnull)
+def test_no_columns_argument():
+    """It should exit with status 2 if there's no --columns argument."""
+    table_function = mock.Mock()
+    try:
+        losser.main(args=[''], table_function=table_function)
+    except SystemExit as err:
+        assert err.code == 2
+    assert not table_function.called
+
+
+def test_help():
+    """It should exit with status 0 if there's a -h argument."""
+    table_function = mock.Mock()
+    try:
+        losser.main(args=['-h'], table_function=table_function)
+    except SystemExit as err:
+        assert err.code == 0
+    assert not table_function.called
+
+
+def test_long_help():
+    """It should exit with status 0 if there's a --help argument."""
+    table_function = mock.Mock()
+    try:
+        losser.main(args=['--help'], table_function=table_function)
+    except SystemExit as err:
+        assert err.code == 0
+    assert not table_function.called
+
+
+def test_help_and_other_args():
+    """It should exit with status 0 if there's a -h argument, even if there are
+    other args as well."""
+    table_function = mock.Mock()
+    try:
+        losser.main(args=['-h', '--columns', 'test_columns.json'],
+                          table_function=table_function)
+    except SystemExit as err:
+        assert err.code == 0
+    assert not table_function.called
+
+
+@mock.patch('sys.stdin')
+def test_columns(mock_stdin):
+    """stdin, --columns and csv=True should be passed to table()."""
+    table_function = mock.Mock()
+
+    # Mock stdin with a file-like object with some JSON text input.
+    mock_stdin.read.return_value = '"foobar"'
+
+    losser.main(
+        args=['--columns', 'test_columns.json'], table_function=table_function)
+
+    table_function.assert_called_once_with(
+        "foobar", "test_columns.json", csv=True)
+
+
+def test_unrecognized_argument():
+    """It should exit with status 2 if given an unrecognized argument."""
+    table_function = mock.Mock()
+    try:
+        losser.main(args=['--columns', 'test_columns.json', '--foobar'],
+                          table_function=table_function)
+    except SystemExit as err:
+        assert err.code == 2
+    assert not table_function.called
+
+
+def _absolute_path(relative_path):
+    return os.path.join(os.path.dirname(os.path.abspath(
+        inspect.getfile(inspect.currentframe()))), relative_path)
+
+
+@mock.patch('sys.stdin')
+def test_input(mock_stdin):
+    """If given the -i argument it should read from the file not stdin."""
+    for arg in ("-i", "--input"):
+        table_function = mock.Mock()
+        losser.main(
+            args=['--columns', 'test_columns.json',
+                  arg, _absolute_path('test_input.json')],
+            table_function=table_function)
+
+        assert not mock_stdin.called
+        table_function.assert_called_once_with(
+            "foobar", "test_columns.json", csv=True)

losser/test_input.json

@@ -0,0 +1 @@
+"foobar"