Add support for LUCI_CONTEXT.

recipe_modules/context/test_api.py

Index: recipe_modules/context/test_api.py
diff --git a/recipe_modules/context/test_api.py b/recipe_modules/context/test_api.py
new file mode 100644
index 0000000000000000000000000000000000000000..81ce74bd798e65c57fbe6548fadebdd3cefe04a9
--- /dev/null
+++ b/recipe_modules/context/test_api.py
@@ -0,0 +1,15 @@
+# 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.
+
+from recipe_engine import recipe_test_api
+
+class ContextTestApi(recipe_test_api.RecipeTestApi):
+  @recipe_test_api.mod_test_data
+  @staticmethod
+  def luci_context(ctx):
+    """Completely mocks LUCI_CONTEXT values."""

[iannucci, 2017/08/04 18:55:51]

I would say something like "Sets the initial LUCI_CONTEXT values for the test."
I would also do **luci_ctx_values instead of ctx.

+    # TODO: more validation
+    if not isinstance(ctx, dict):  # pragma: no cover
+      raise TypeError('Expecting a dict')
+    return ctx