Fix error causing instrumentation tests to run with trials disabled on WV N & O bots.

Bug: 997309
Change-Id: I6f29983c9d5c18c6837a791c1a4abcf0d15ddfef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1779854
Commit-Queue: Andrew Luo <[email protected]>
Reviewed-by: Ben Pastene <[email protected]>
Cr-Commit-Position: refs/heads/master@{#694283}
diff --git a/testing/buildbot/generate_buildbot_json_unittest.py b/testing/buildbot/generate_buildbot_json_unittest.py
index 5fdb24c0..72386fe 100755
--- a/testing/buildbot/generate_buildbot_json_unittest.py
+++ b/testing/buildbot/generate_buildbot_json_unittest.py
@@ -664,6 +664,33 @@
 }
 """
 
+CONFLICTING_COMPOSITION_TEST_SUITES = """\
+{
+  'basic_suites': {
+    'bar_tests': {
+      'baz_tests': {
+        'args': [
+          '--bar',
+        ],
+      }
+    },
+    'foo_tests': {
+      'baz_tests': {
+        'args': [
+          '--foo',
+        ],
+      }
+    },
+  },
+  'compound_suites': {
+    'foobar_tests': [
+      'foo_tests',
+      'bar_tests',
+    ],
+  },
+}
+"""
+
 DUPLICATES_COMPOSITION_TEST_SUITES = """\
 {
   'basic_suites': {
@@ -2042,6 +2069,17 @@
       fbb.check_input_file_consistency(verbose=True)
     self.assertFalse(fbb.printed_lines)
 
+  def test_composition_test_suites_no_conflicts(self):
+    fbb = FakeBBGen(COMPOSITION_GTEST_SUITE_WATERFALL,
+                    CONFLICTING_COMPOSITION_TEST_SUITES,
+                    EMPTY_PYL_FILE,
+                    EMPTY_PYL_FILE,
+                    LUCI_MILO_CFG)
+    with self.assertRaisesRegexp(generate_buildbot_json.BBGenErr,
+                                 'Conflicting test definitions.*'):
+      fbb.check_input_file_consistency(verbose=True)
+    self.assertFalse(fbb.printed_lines)
+
   def test_composition_test_suites_no_duplicate_names(self):
     fbb = FakeBBGen(COMPOSITION_GTEST_SUITE_WATERFALL,
                     DUPLICATES_COMPOSITION_TEST_SUITES,