diff --git a/testing/mozbase/moztest/moztest/resolve.py b/testing/mozbase/moztest/moztest/resolve.py
index 0299405ea20a..48ed4229bd63 100644
--- a/testing/mozbase/moztest/moztest/resolve.py
+++ b/testing/mozbase/moztest/moztest/resolve.py
@@ -28,8 +28,8 @@ def WebglSuite(name):
         'aliases': (name,),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'plain', 'subsuite': name, 'test_paths': None},
-        'task_regex': ['mochitest-' + name + '(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-gpu)?(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-' + name + '($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     }
 
 
@@ -74,63 +74,63 @@ TEST_SUITES = {
         'aliases': ('a11y', 'ally'),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'a11y', 'test_paths': None},
-        'task_regex': ['mochitest-a11y(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-a11y($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-browser': {
         'aliases': ('bc', 'browser-chrome'),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'browser-chrome', 'test_paths': None},
-        'task_regex': ['mochitest-browser-chrome(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-browser-chrome($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-chrome': {
         'aliases': ('mc',),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'chrome', 'test_paths': None},
-        'task_regex': ['mochitest-chrome(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-chrome($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-clipboard': {
         'aliases': ('cl', 'clipboard',),
         'mach_command': 'mochitest',
         'kwargs': {'subsuite': 'clipboard', 'test_paths': None},
-        'task_regex': ['mochitest-clipboard(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-clipboard($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-devtools': {
         'aliases': ('dt', 'devtools-chrome'),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'browser-chrome', 'subsuite': 'devtools', 'test_paths': None},
-        'task_regex': ['mochitest-devtools-chrome(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-devtools-chrome($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-gpu': {
         'aliases': ('gpu',),
         'mach_command': 'mochitest',
         'kwargs': {'subsuite': 'gpu', 'test_paths': None},
-        'task_regex': ['mochitest-gpu(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-gpu)?(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-gpu($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-media': {
         'aliases': ('mpm', 'plain-media'),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'plain', 'subsuite': 'media', 'test_paths': None},
-        'task_regex': ['mochitest-media(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest-media($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-plain': {
         'aliases': ('mp', 'plain',),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'plain', 'test_paths': None},
-        'task_regex': ['mochitest(?:-e10s)?(?:-1)?$',
-                       'test-verify(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['mochitest(?!-a11y|-browser|-chrome|-clip|-devtools|-gpu|-media|-screen)($|.*(-1|[^0-9])$)',  # noqa
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
     'mochitest-screenshots': {
         'aliases': ('ss', 'screenshots-chrome'),
         'mach_command': 'mochitest',
         'kwargs': {'flavor': 'browser-chrome', 'subsuite': 'screenshots', 'test_paths': None},
-        'task_regex': ['browser-screenshots(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['browser-screenshots($|.*(-1|[^0-9])$)'],
     },
     'mochitest-webgl1-core': WebglSuite('webgl1-core'),
     'mochitest-webgl1-ext': WebglSuite('webgl1-ext'),
@@ -145,40 +145,40 @@ TEST_SUITES = {
         'aliases': ('rr',),
         'mach_command': 'reftest',
         'kwargs': {'tests': None},
-        'task_regex': ['(opt|debug)-reftest(?:-no-accel|-gpu|-stylo)?(?:-e10s)?(?:-1)?$',
-                       'test-verify-gpu(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['(opt|debug)-reftest($|.*(-1|[^0-9])$)',
+                       'test-verify-gpu($|.*(-1|[^0-9])$)'],
     },
     'robocop': {
         'mach_command': 'robocop',
         'kwargs': {'test_paths': None},
-        'task_regex': ['robocop(?:-e10s)?(?:-1)?$'],
+        'task_regex': ['robocop($|.*(-1|[^0-9])$)'],
     },
     'web-platform-tests': {
         'aliases': ('wpt',),
         'mach_command': 'web-platform-tests',
         'kwargs': {'include': []},
-        'task_regex': ['web-platform-tests(?:-reftests|-wdspec)?(?:-e10s)?(?:-1)?$',
+        'task_regex': ['web-platform-tests($|.*(-1|[^0-9])$)',
                        'test-verify-wpt-e10s'],
     },
     'web-platform-tests-testharness': {
         'aliases': ('wpt',),
         'mach_command': 'web-platform-tests',
         'kwargs': {'include': []},
-        'task_regex': ['web-platform-tests(?:-e10s)?(?:-1)?$',
+        'task_regex': ['web-platform-tests(?!-reftest|-wdspec)($|.*(-1|[^0-9])$)',
                        'test-verify-wpt-e10s'],
     },
     'web-platform-tests-reftest': {
         'aliases': ('wpt',),
         'mach_command': 'web-platform-tests',
         'kwargs': {'include': []},
-        'task_regex': ['web-platform-tests-reftests(?:-e10s)?(?:-1)?$',
+        'task_regex': ['web-platform-tests-reftests($|.*(-1|[^0-9])$)',
                        'test-verify-wpt-e10s'],
     },
     'web-platform-tests-wdspec': {
         'aliases': ('wpt',),
         'mach_command': 'web-platform-tests',
         'kwargs': {'include': []},
-        'task_regex': ['web-platform-tests-wdspec(?:-e10s)?(?:-1)?$',
+        'task_regex': ['web-platform-tests-wdspec($|.*(-1|[^0-9])$)',
                        'test-verify-wpt-e10s'],
     },
     'valgrind': {
@@ -190,7 +190,8 @@ TEST_SUITES = {
         'aliases': ('x',),
         'mach_command': 'xpcshell-test',
         'kwargs': {'test_file': 'all'},
-        'task_regex': ['xpcshell(?:-1)?$', 'test-verify(?:-1)?$'],
+        'task_regex': ['xpcshell($|.*(-1|[^0-9])$)',
+                       'test-verify($|.*(-1|[^0-9])$)'],
     },
 }
 
diff --git a/testing/mozbase/moztest/tests/test_resolve.py b/testing/mozbase/moztest/tests/test_resolve.py
index e960bb94a74b..0c6db8a15dc0 100644
--- a/testing/mozbase/moztest/tests/test_resolve.py
+++ b/testing/mozbase/moztest/tests/test_resolve.py
@@ -3,7 +3,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 # flake8: noqa: E501
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 import cPickle as pickle
 import os
@@ -407,6 +407,8 @@ class TestTestResolver(Base):
             'mochitest-plain': [
                 'test-linux64/opt-mochitest',
                 'test-linux64/debug-mochitest-e10s',
+                # this isn't a real task but the regex would match it if it were
+                'test-linux64/opt-mochitest-plain',
             ],
             'mochitest-screenshots': [
                 'test-linux64/opt-browser-screenshots-1',
@@ -425,6 +427,7 @@ class TestTestResolver(Base):
             'web-platform-tests': [
                 'test-linux64/opt-web-platform-tests-e10s-1',
                 'test-linux64/opt-web-platform-tests-reftests-e10s-1',
+                'test-linux64/opt-web-platform-tests-reftest-e10s-1',
                 'test-linux64/opt-web-platform-tests-wdspec-e10s-1',
                 'test-linux64/opt-web-platform-tests-1',
             ],
@@ -450,6 +453,7 @@ class TestTestResolver(Base):
             return any(re.search(pattern, task) for pattern in regexes)
 
         for suite, expected in sorted(test_cases.items()):
+            print(suite)
             regexes = TEST_SUITES[suite]['task_regex']
             assert set(filter(match_task, TASK_LABELS)) == set(expected)