diff --git a/test/excludes/_wercker/test-mjit-wait/TestParallel.rb b/test/excludes/_wercker/test-mjit-wait/TestParallel.rb
new file mode 100644
index 0000000000..e241a78b47
--- /dev/null
+++ b/test/excludes/_wercker/test-mjit-wait/TestParallel.rb
@@ -0,0 +1,2 @@
+# https://app.wercker.com/ruby/ruby/runs/test-mjit-wait/5bd040d19b1e440006d52516?step=5bd0410c591ca8000721e3e4
+exclude(:test_separate, 'this test randomly fails with --jit-wait')
diff --git a/test/excludes/_wercker/test-mjit-wait/TestThreadQueue.rb b/test/excludes/_wercker/test-mjit-wait/TestThreadQueue.rb
new file mode 100644
index 0000000000..5d0ba88cf4
--- /dev/null
+++ b/test/excludes/_wercker/test-mjit-wait/TestThreadQueue.rb
@@ -0,0 +1,2 @@
+# https://app.wercker.com/ruby/ruby/runs/test-mjit-wait/5bcfd19aa9806e000655c598?step=5bcfd1d5acc4510006e00f77
+exclude(:test_queue_with_trap, 'this test randomly fails with --jit-wait')
diff --git a/test/excludes/_wercker/TestThreadQueue.rb b/test/excludes/_wercker/test-mjit/TestThreadQueue.rb
similarity index 55%
rename from test/excludes/_wercker/TestThreadQueue.rb
rename to test/excludes/_wercker/test-mjit/TestThreadQueue.rb
index b7a831f1b5..2a968ab04c 100644
--- a/test/excludes/_wercker/TestThreadQueue.rb
+++ b/test/excludes/_wercker/test-mjit/TestThreadQueue.rb
@@ -1,2 +1,2 @@
 # https://app.wercker.com/ruby/ruby/runs/test-mjit/5bcf51409b1e440006d47831?step=5bcf517d87436a000649326d
-exclude(:test_queue_with_trap, 'this test randomly fails with --jit or --jit-wait')
+exclude(:test_queue_with_trap, 'this test fails with --jit')
diff --git a/wercker.yml b/wercker.yml
index b907a1ddf6..71d15a3739 100644
--- a/wercker.yml
+++ b/wercker.yml
@@ -1,6 +1,6 @@
 #
 # Wercker is dedicated for testing MJIT. Please use Travis or AppVeyor for non-MJIT testing.
-# This runs all Ruby tests with --jit-wait, which synchronously JITs all methods.
+# This runs all Ruby tests with --jit, or --jit-wait which synchronously JITs all methods.
 #
 box: ruby:2.5-stretch
 no-response-timeout: 30
@@ -27,7 +27,7 @@ test-mjit:
         code: /usr/bin/sudo -H -u test -- make test RUN_OPTS="--disable-gems --jit --jit-warnings"
     - script:
         name: make test-all (JIT)
-        code: /usr/bin/sudo -H -u test -- make test-all RUN_OPTS="--disable-gems --jit --jit-warnings" TESTOPTS="--color=never --job-status=normal --longest 10 --subprocess-timeout-scale=3.0 --excludes=test/excludes/_wercker"
+        code: /usr/bin/sudo -H -u test -- make test-all RUN_OPTS="--disable-gems --jit --jit-warnings" TESTOPTS="--color=never --job-status=normal --longest 10 --subprocess-timeout-scale=3.0 --excludes=test/excludes/_wercker/test-mjit"
     - script:
         name: make test-spec (JIT)
         code: /usr/bin/sudo -H -u test -- make test-spec RUN_OPTS="--disable-gems --jit --jit-warnings"
@@ -60,11 +60,11 @@ test-mjit-wait:
         code: /usr/bin/sudo -H -u test -- make test RUN_OPTS="--disable-gems --jit-wait --jit-warnings"
     # split test-all to 2 steps to loosen timeout
     - script:
-        name: make test-all1 (JIT wait)
-        code: /usr/bin/sudo -H -u test -- make test-all RUN_OPTS="--disable-gems --jit-wait --jit-warnings" TESTS="test/ruby/ test/testunit/" TESTOPTS="--color=never --job-status=normal --longest 10 --subprocess-timeout-scale=3.0 --excludes=test/excludes/_wercker"
+        name: make test-all1 (JIT wait) # only: test/ruby/, test/testunit/
+        code: /usr/bin/sudo -H -u test -- make test-all RUN_OPTS="--disable-gems --jit-wait --jit-warnings" TESTS="test/ruby/ test/testunit/" TESTOPTS="--color=never --job-status=normal --longest 10 --subprocess-timeout-scale=3.0 --excludes=test/excludes/_wercker/test-mjit-wait"
     - script:
-        name: make test-all2 (JIT wait)
-        code: /usr/bin/sudo -H -u test -- make test-all RUN_OPTS="--disable-gems --jit-wait --jit-warnings" TESTOPTS="--exclude test/ruby/ --exclude test/testunit/ --color=never --job-status=normal --longest 10 --subprocess-timeout-scale=3.0 --excludes=test/excludes/_wercker"
+        name: make test-all2 (JIT wait) # except: test/ruby/, test/testunit/
+        code: /usr/bin/sudo -H -u test -- make test-all RUN_OPTS="--disable-gems --jit-wait --jit-warnings" TESTOPTS="--exclude test/ruby/ --exclude test/testunit/ --color=never --job-status=normal --longest 10 --subprocess-timeout-scale=3.0 --excludes=test/excludes/_wercker/test-mjit-wait"
     - script:
         name: make test-spec (JIT wait)
         code: /usr/bin/sudo -H -u test -- make test-spec RUN_OPTS="--disable-gems --jit-wait --jit-warnings"