Improve CLI interface of C++ enums to Java generator

build/android/gyp/java_cpp_enum_tests.py

Index: build/android/gyp/java_cpp_enum_tests.py
diff --git a/build/android/gyp/java_cpp_enum_tests.py b/build/android/gyp/java_cpp_enum_tests.py
index 75e6671ed1616f4601dc07090f9ac7d60609f683..44f9766c82c98d6c6bab67764d89ee4bc6640282 100755
--- a/build/android/gyp/java_cpp_enum_tests.py
+++ b/build/android/gyp/java_cpp_enum_tests.py
@@ -14,6 +14,7 @@ import os
 import sys
 import unittest
 
+import java_cpp_enum
 from java_cpp_enum import EnumDefinition, GenerateOutput, GetScriptName
 from java_cpp_enum import HeaderParser
 
@@ -151,6 +152,14 @@ public class ClassName {
     with self.assertRaises(Exception):
       HeaderParser(test_data).ParseDefinitions()
 
+  def testParseReturnsEmptyListWithoutDirectives(self):
+    test_data = """
+      enum EnumName {
+        VALUE_ONE,
+      };
+    """.split('\n')
+    self.assertEqual([], HeaderParser(test_data).ParseDefinitions())
+
   def testParseEnumClass(self):
     test_data = """
       // GENERATED_JAVA_ENUM_PACKAGE: test.namespace
@@ -403,6 +412,15 @@ public class ClassName {
     definition.Finalize()
     self.assertEqual(['A', 'B', 'NAME_LAST'], definition.entries.keys())
 
+  def testGenerateThrowsOnEmptyInput(self):
+    with self.assertRaises(Exception):
+      original_do_parse = java_cpp_enum.DoParseHeaderFile
+      try:
+        java_cpp_enum.DoParseHeaderFile = lambda _: []
+        java_cpp_enum.DoGenerate('dir', ['file'])
+      finally:
+        java_cpp_enum.DoParseHeaderFile = original_do_parse
+
 def main(argv):
   parser = optparse.OptionParser()
   parser.add_option("--stamp", help="File to touch on success.")