--- a/js/moz.build
+++ b/js/moz.build
@@ -6,8 +6,14 @@ with Files("**"):
     BUG_COMPONENT = component_engine
 
 for header in ('GCAnnotations.h', 'GCAPI.h', 'HeapAPI.h', 'RootingAPI.h', 'SliceBudget.h', 'SweepingAPI.h', 'TraceKind.h', 'TracingAPI.h', 'WeakMapPtr.h', 'GCHashTable.h', 'GCPolicyAPI.h', 'GCVariant.h', 'GCVector.h'):
     with Files('public/' + header):
         BUG_COMPONENT = component_gc
 
 with Files('public/TrackedOptimizationInfo.h'):
     BUG_COMPONENT = component_jit
+
+with Files("src/**"):
+    SCHEDULES.inclusive += ['jittest', 'jsreftest']
+
+with Files("public/**"):
+    SCHEDULES.inclusive += ['jittest', 'jsreftest']

--- a/moz.build
+++ b/moz.build
@@ -50,16 +50,28 @@ with Files('README.txt'):
 
 with Files("nsprpub/**"):
     BUG_COMPONENT = ("NSPR", "NSPR")
 
 with Files('**/Makefile.in'):
     BUG_COMPONENT = ('Core', 'Build Config')
     FINAL = True
 
+with Files("**/*.js"):
+    SCHEDULES.inclusive += ['test-verify']
+
+with Files("**/*.html"):
+    SCHEDULES.inclusive += ['test-verify']
+
+with Files("**/*.xhtml"):
+    SCHEDULES.inclusive += ['test-verify']
+
+with Files("**/*.xul"):
+    SCHEDULES.inclusive += ['test-verify']
+
 CONFIGURE_SUBST_FILES += [
     'config/autoconf.mk',
     'config/emptyvars.mk',
 ]
 
 if CONFIG['ENABLE_CLANG_PLUGIN']:
     DIRS += ['build/clang-plugin']
 

--- a/python/mozbuild/mozbuild/schedules.py
+++ b/python/mozbuild/mozbuild/schedules.py
@@ -10,32 +10,36 @@ skip-unless-schedules optimizations in t
 from __future__ import absolute_import, unicode_literals, print_function
 
 # TODO: ideally these lists could be specified in moz.build itself
 
 INCLUSIVE_COMPONENTS = [
     'py-lint',
     'js-lint',
     'yaml-lint',
+    # inclusive test suites -- these *only* run when certain files have changed
+    'jittest',
+    'test-verify',
+    'test-verify-wpt',
+    'jsreftest',
 ]
 INCLUSIVE_COMPONENTS = sorted(INCLUSIVE_COMPONENTS)
 
 EXCLUSIVE_COMPONENTS = [
     # os families
     'android',
     'linux',
     'macosx',
     'windows',
     # test suites
     'awsy',
     'cppunittest',
     'firefox-ui',
     'geckoview',
     'gtest',
-    'jittest',
     'marionette',
     'mochitest',
     'reftest',
     'robocop',
     'talos',
     'telemetry-tests-client',
     'xpcshell',
     'xpcshell-coverage',

--- a/taskcluster/ci/test/compiled.yml
+++ b/taskcluster/ci/test/compiled.yml
@@ -66,16 +66,12 @@ jittest:
             macosx.*: 1
             default: 6
     mozharness:
         chunked:
             by-test-platform:
                 windows.*: false
                 macosx.*: false
                 default: true
-    when:
-        files-changed:
-            - js/src/**
-            - js/public/**
     tier:
         by-test-platform:
             windows10-64-asan.*: 3
             default: default

--- a/taskcluster/ci/test/misc.yml
+++ b/taskcluster/ci/test/misc.yml
@@ -49,17 +49,17 @@ telemetry-tests-client:
         config:
             by-test-platform:
                 linux.*:
                     - remove_executables.py
                 windows.*: []
 
 test-verify:
     description: "Extra verification of tests modified on this push"
-    suite: test-verification
+    suite: test-verify
     treeherder-symbol: tc(TV)
     loopback-video: true
     max-run-time: 5400
     allow-software-gl-layers: false
     run-on-projects:
         by-test-platform:
             # do not run on ccov; see also the enable_code_coverage transform
             linux64-ccov/.*: []
@@ -83,14 +83,8 @@ test-verify:
                 macosx.*:
                     - remove_executables.py
                     - unittests/mac_unittest.py
                 windows.*:
                     - unittests/win_taskcluster_unittest.py
         no-read-buildbot-config: true
         extra-options:
             - --verify
-    when:
-        files-changed:
-            - '**/*.js'
-            - '**/*.html'
-            - '**/*.xhtml'
-            - '**/*.xul'

--- a/taskcluster/ci/test/reftest.yml
+++ b/taskcluster/ci/test/reftest.yml
@@ -70,20 +70,16 @@ jsreftest:
         by-test-platform:
             linux64-jsdcov/opt: false
             windows10-64/debug: both
             default: true
     max-run-time:
         by-test-platform:
             android.*: 7200
             default: 3600
-    when:
-        files-changed:
-            - js/src/**
-            - js/public/**
     tier:
         by-test-platform:
             linux64-qr/.*: 1
             windows10-64-asan.*: 3
             default: default
 
 reftest:
     description: "Reftest run"

--- a/taskcluster/ci/test/web-platform.yml
+++ b/taskcluster/ci/test/web-platform.yml
@@ -139,11 +139,8 @@ test-verify-wpt:
             default: built-projects
     tier:
         by-test-platform:
             windows10-64-asan.*: 3
             default: 2
     mozharness:
         extra-options:
             - --verify
-    when:
-        files-changed:
-            - 'testing/web-platform/tests/**'

--- a/taskcluster/taskgraph/transforms/tests.py
+++ b/taskcluster/taskgraph/transforms/tests.py
@@ -373,21 +373,16 @@ test_description_schema = Schema({
     'test-platform': basestring,
 
     # the name of the test (the key in tests.yml)
     'test-name': basestring,
 
     # the product name, defaults to firefox
     Optional('product'): basestring,
 
-    # conditional files to determine when these tests should be run
-    Optional('when'): Any({
-        Optional('files-changed'): [basestring],
-    }),
-
     Optional('worker-type'): optionally_keyed_by(
         'test-platform',
         Any(basestring, None),
     ),
 
 }, required=True)
 
 
@@ -649,17 +644,17 @@ def handle_suite_category(config, tests)
             suite = flavor = test['suite']
 
         test.setdefault('attributes', {})
         test['attributes']['unittest_suite'] = suite
         test['attributes']['unittest_flavor'] = flavor
 
         script = test['mozharness']['script']
         category_arg = None
-        if suite == 'test-verification':
+        if suite == 'test-verify':
             pass
         elif script == 'android_emulator_unittest.py':
             category_arg = '--test-suite'
         elif script == 'desktop_unittest.py':
             category_arg = '--{}-suite'.format(suite)
 
         if category_arg:
             test['mozharness'].setdefault('extra-options', [])
@@ -672,17 +667,16 @@ def handle_suite_category(config, tests)
 
 @transforms.add
 def enable_code_coverage(config, tests):
     """Enable code coverage for the linux64-ccov/opt & linux64-jsdcov/opt & win64-ccov/debug
     build-platforms"""
     for test in tests:
         if 'ccov' in test['build-platform'] and not test['test-name'].startswith('test-verify'):
             test['mozharness'].setdefault('extra-options', []).append('--code-coverage')
-            test['when'] = {}
             test['instance-size'] = 'xlarge'
             # Ensure we don't run on inbound/autoland/beta, but if the test is try only, ignore it
             if 'mozilla-central' in test['run-on-projects'] or \
                     test['run-on-projects'] == 'built-projects':
                 test['run-on-projects'] = ['mozilla-central', 'try']
 
             if 'talos' in test['test-name']:
                 test['max-run-time'] = 7200
@@ -986,34 +980,31 @@ def make_job_description(config, tests):
         }
         jobdesc['treeherder'] = {
             'symbol': test['treeherder-symbol'],
             'kind': 'test',
             'tier': test['tier'],
             'platform': test.get('treeherder-machine-platform', test['build-platform']),
         }
 
-        if test.get('when'):
-            jobdesc['when'] = test['when']
+        suite = attributes['unittest_suite']
+        if suite in INCLUSIVE_COMPONENTS:
+            # if this is an "inclusive" test, then all files which might
+            # cause it to run are annotated with SCHEDULES in moz.build,
+            # so do not include the platform or any other components here
+            schedules = [suite]
         else:
-            suite = attributes['unittest_suite']
-            if suite in INCLUSIVE_COMPONENTS:
-                # if this is an "inclusive" test, then all files which might
-                # cause it to run are annotated with SCHEDULES in moz.build,
-                # so do not include the platform or any other components here
-                schedules = [suite]
-            else:
-                schedules = [suite, platform_family(test['build-platform'])]
+            schedules = [suite, platform_family(test['build-platform'])]
 
-            if config.params['project'] != 'try':
-                # for non-try branches, include SETA
-                jobdesc['optimization'] = {'skip-unless-schedules-or-seta': schedules}
-            else:
-                # otherwise just use skip-unless-schedules
-                jobdesc['optimization'] = {'skip-unless-schedules': schedules}
+        if config.params['project'] != 'try':
+            # for non-try branches, include SETA
+            jobdesc['optimization'] = {'skip-unless-schedules-or-seta': schedules}
+        else:
+            # otherwise just use skip-unless-schedules
+            jobdesc['optimization'] = {'skip-unless-schedules': schedules}
 
         run = jobdesc['run'] = {}
         run['using'] = 'mozharness-test'
         run['test'] = test
 
         jobdesc['worker-type'] = test.pop('worker-type')
 
         yield jobdesc

--- a/testing/web-platform/moz.build
+++ b/testing/web-platform/moz.build
@@ -94,16 +94,20 @@ with Files("mach*"):
     BUG_COMPONENT = ("Testing", "web-platform-tests")
 
 with Files("*.py"):
     BUG_COMPONENT = ("Testing", "web-platform-tests")
 
 with Files("tests/*.md"):
     BUG_COMPONENT = ("Testing", "web-platform-tests")
 
+with Files("tests/**"):
+    BUG_COMPONENT = ("Testing", "web-platform-tests")
+    SCHEDULES.inclusive += ['test-verify-wpt']
+
 with Files("tests/LICENSE"):
     BUG_COMPONENT = ("Testing", "web-platform-tests")
 
 with Files("tests/check_stability.ini"):
     BUG_COMPONENT = ("Testing", "web-platform-tests")
 
 with Files("tests/config.default.json"):
     BUG_COMPONENT = ("Testing", "web-platform-tests")