Add unit tests for overrides in multi-repo workflow

unittests/override_test.py

Index: unittests/override_test.py
diff --git a/unittests/override_test.py b/unittests/override_test.py
new file mode 100755
index 0000000000000000000000000000000000000000..b0771f1f70aab2288ed1c30bdb6068a5d8260cdf
--- /dev/null
+++ b/unittests/override_test.py
@@ -0,0 +1,85 @@
+#!/usr/bin/env python
+# Copyright 2017 The LUCI Authors. All rights reserved.
+# Use of this source code is governed under the Apache License, Version 2.0
+# that can be found in the LICENSE file.
+
+import subprocess
+import sys
+import unittest
+
+import repo_test_util
+
+
+class TestOverride(repo_test_util.RepoTest):
+  def test_simple(self):
+    repos = self.repo_setup({
+        'a': [],
+        'a1': [],
+        'b': ['a'],
+    })
+
+    a_c1 = self.update_recipe_module(repos['a'], 'a_module', {'foo': ['bar']})
+    b_c1_rev = self.update_recipes_cfg(
+        'b', self.updated_package_spec_pb(repos['b'], 'a', a_c1['revision']))
+    b_c2 = self.update_recipe(
+        repos['b'], 'b_recipe', ['a/a_module'], [('a_module', 'foo')])
+
+    # Training the recipes should work.
+    self.train_recipes(repos['b'])
+
+    # Using a no-op override should also work.
+    self.train_recipes(repos['b'], overrides=[('a', repos['a']['root'])])
+
+    # Using an override pointing to empty repo should fail.
+    with self.assertRaises(subprocess.CalledProcessError) as cm:
+      self.train_recipes(repos['b'], overrides=[('a', repos['a1']['root'])])
+    self.assertIn(
+        'Exception: While generating results for \'b_recipe\': ImportError: '
+        'No module named a_module',
+        cm.exception.output)
+
+  def test_dependency_conflict(self):
+    repos = self.repo_setup({
+        'a': [],
+        'b': ['a'],
+        'b1': ['a'],
+        'c': ['a', 'b'],
+    })
+
+    a_c1 = self.update_recipe_module(repos['a'], 'a_module', {'foo': ['bar']})
+    b_c1_rev = self.update_recipes_cfg(
+        'b', self.updated_package_spec_pb(repos['b'], 'a', a_c1['revision']))
+    b1_c1_rev = self.update_recipes_cfg(
+        'b1', self.updated_package_spec_pb(repos['b1'], 'a', a_c1['revision']))
+
+    a_c2 = self.update_recipe_module(repos['a'], 'a_module', {'foo': ['baz']})
+    b_c2_rev = self.update_recipes_cfg(
+        'b', self.updated_package_spec_pb(repos['b'], 'a', a_c2['revision']))
+
+    c_spec = self.get_package_spec(repos['c'])
+    c_spec.deps['a'].revision = a_c2['revision']
+    c_spec.deps['b'].revision = b_c2_rev
+    c_c1 = self.update_recipes_cfg('c', c_spec.dump())
+
+    c_c2 = self.update_recipe(
+        repos['c'], 'c_recipe', ['a/a_module'], [('a_module', 'foo')])
+
+    # Training the recipes should work.
+    self.train_recipes(repos['c'])
+
+    # Trying to override just the b repo should fail (conflicting revisions
+    # of the a repo).
+    with self.assertRaises(subprocess.CalledProcessError) as cm:
+      self.train_recipes(repos['c'], overrides=[('b', repos['b1']['root'])])
+    # TODO(phajdan.jr): assert on full message after making exception printable.
+    self.assertIn('InconsistentDependencyGraphError', cm.exception.output)
+
+    # The solution is to also override the a repo to make it clear what revision
+    # should be used.
+    self.train_recipes(
+        repos['c'],
+        overrides=[('b', repos['b1']['root']), ('a', repos['a']['root'])])
+
+
+if __name__ == '__main__':
+  sys.exit(unittest.main())