Implement tests for the diff tool

pytest_django_queries/cli.py

@@ -8,7 +8,8 @@
 
 from pytest_django_queries.diff import DiffGenerator
 from pytest_django_queries.entry import flatten_entries
-from pytest_django_queries.plugin import DEFAULT_RESULT_FILENAME
+from pytest_django_queries.plugin import (
+    DEFAULT_RESULT_FILENAME, DEFAULT_OLD_RESULT_FILENAME)
 from pytest_django_queries.tables import print_entries, print_entries_as_html
 
 HERE = dirname(__file__)
@@ -73,7 +74,7 @@ def html(input_file, template):
 
 @main.command()
 @click.argument(
-    'left_file', type=JsonFileParamType('r'))
+    'left_file', type=JsonFileParamType('r'), default=DEFAULT_OLD_RESULT_FILENAME)
 @click.argument(
     'right_file', type=JsonFileParamType('r'), default=DEFAULT_RESULT_FILENAME)
 def diff(left_file, right_file):
@@ -93,17 +94,5 @@ def diff(left_file, right_file):
             click.secho(line, fg=fg_color)
 
 
-@main.command()
-@click.argument(
-    'left_file', type=JsonFileParamType('r'))
-@click.argument(
-    'right_file', type=JsonFileParamType('r'), default=DEFAULT_RESULT_FILENAME)
-def ediff(left_file, right_file):
-    """Render the diff as HTML instead of a diff table."""
-    left = flatten_entries(left_file)
-    right = flatten_entries(right_file)
-    raise NotImplementedError
-
-
 if __name__ == '__main__':
     main()

pytest_django_queries/diff.py

@@ -69,7 +69,6 @@ def __init__(self, left=None, right=None):
 
         self.left = left
         self.right = right
-        self.diff = None
 
     def _diff_from_newest(self):
         """
@@ -99,10 +98,11 @@ def left_count(self):
     def right_count(self):
         return str(self.right.query_count) if self.right else _NA_CHAR
 
-    def to_string(self, lengths):
-        if self.diff is None:
-            self.diff = self._diff_from_newest()
+    @property
+    def diff(self):
+        return self._diff_from_newest()
 
+    def to_string(self, lengths):
         return entry_row(self, lengths=lengths)
 
 
@@ -161,13 +161,16 @@ def _generate_mapping(self):
         self._map_side(self.entries_left, 'left')
         self._map_side(self.entries_right, 'right')
 
-    def iter_module(self, module_entries):
+    def _iter_module(self, module_entries):
         yield self.header_rows
-        for test_comparison in module_entries.values():  # type: SingleEntryComparison
+        for _, test_comparison in sorted(module_entries.items()):  # type: SingleEntryComparison
             yield test_comparison.to_string(lengths=self.longest_props)
 
-    def __iter__(self):
-        for module_name, module_entries in self._mapping.items():
+    def _iter_modules(self):
+        for module_name, module_entries in sorted(self._mapping.items()):
             yield (
                 format_underscore_name_to_human(module_name),
-                self.iter_module(module_entries))
+                self._iter_module(module_entries))
+
+    def __iter__(self):
+        return self._iter_modules()

pytest_django_queries/plugin.py

@@ -6,6 +6,7 @@
 # Defines the plugin marker name
 PYTEST_QUERY_COUNT_MARKER = 'count_queries'
 DEFAULT_RESULT_FILENAME = '.pytest-queries'
+DEFAULT_OLD_RESULT_FILENAME = '.pytest-queries.old'
 
 
 def _set_session(config, new_session):

tests/conftest.py

@@ -1 +1,26 @@
+import pytest
+
+from pytest_django_queries.entry import flatten_entries
+
 pytest_plugins = 'pytester'
+
+
+@pytest.fixture
+def valid_comparison_entries():
+    left = {
+        "test_module": {
+            "test_improved_func": {"query-count": 20},
+            "test_degraded_func": {"query-count": 15},
+            "test_unchanged_func": {"query-count": 1},
+        }
+    }
+
+    right = {
+        "test_module": {
+            "test_improved_func": {"query-count": 19},
+            "test_degraded_func": {"query-count": 16},
+            "test_unchanged_func": {"query-count": 1},
+        }
+    }
+
+    return left, right

tests/test_cli_diff.py

@@ -0,0 +1,28 @@
+import json
+
+from click.testing import CliRunner
+from pytest_django_queries import cli
+
+
+def test_export_to_html_using_custom_template(testdir, valid_comparison_entries):
+    left, right = valid_comparison_entries
+    right["another_module"] = {"test_new_test": {"query-count": 1}}
+    testdir.makefile('json', left=json.dumps(left))
+    testdir.makefile('json', right=json.dumps(right))
+
+    runner = CliRunner()
+    result = runner.invoke(cli.main, ['diff', 'left.json', 'right.json'])
+    assert result.exit_code == 0, result.stdout
+    assert repr(result.stdout) == repr(u"""\
+# another module
+  test name          \tleft count \tright count
+  -------------------\t-----------\t-----------
++ new test           \t          -\t          1
+
+# module
+  test name          \tleft count \tright count
+  -------------------\t-----------\t-----------
+- degraded func      \t         15\t         16
++ improved func      \t         20\t         19
+  unchanged func     \t          1\t          1
+""")

tests/test_diff.py

@@ -0,0 +1,51 @@
+import pytest
+
+from pytest_django_queries.diff import DiffGenerator
+from pytest_django_queries.entry import flatten_entries
+
+
+@pytest.mark.parametrize('right', (
+    {},
+    {"test_module": {}},
+    {"test_module_123": {}}
+))
+def test_comparison_deleted_test_triggers_negative_review(right):
+    left = flatten_entries({"test_module": {"test_deleted_func": {"query-count": 1}}})
+    right = flatten_entries(right)
+    module_diffs = list(next(iter(DiffGenerator(left, right)))[1])
+
+    # We expect it to:
+    # 1. start with '-'
+    # 2. to give a left value of 1
+    # 3. to give a right value of N/A
+    assert '- deleted func     \t          1\t          -' in module_diffs
+
+
+@pytest.mark.parametrize('left', (
+    {},
+    {"test_module": {}},
+    {"test_module_123": {}}
+))
+def test_comparison_new_test_triggers_positive_review(left):
+    left = flatten_entries(left)
+    right = flatten_entries({"test_module": {"test_added_func": {"query-count": 1}}})
+    module_diffs = list(next(iter(DiffGenerator(left, right)))[1])
+
+    # We expect it to:
+    # 1. start with '+'
+    # 2. to give a left value of N/A
+    # 3. to give a right value of 1
+    assert '+ added func     \t          -\t          1' in module_diffs
+
+
+def test_comparison_diff_is_correct(valid_comparison_entries):
+    left, right = valid_comparison_entries
+    left = flatten_entries(left)
+    right = flatten_entries(right)
+
+    module_diffs = list(next(iter(DiffGenerator(left, right)))[1])
+
+    assert len(module_diffs) == 4  # 3 tests + header
+    assert '+ improved func      \t         20\t         19' in module_diffs
+    assert '- degraded func      \t         15\t         16' in module_diffs
+    assert '  unchanged func     \t          1\t          1' in module_diffs