MONGOID-5549 Fix app spec failures on JRuby (#5564)

Author: comandeo-mongo

.evergreen/config.yml

@@ -763,16 +763,15 @@ buildvariants:
   tasks:
      - name: "test"
 
-# https://jira.mongodb.org/browse/MONGOID-5549
-# - matrix_name: app-tests-jruby
-#   matrix_spec:
-#     jruby: ["jruby-9.3"]
-#     driver: ["current"]
-#     mongodb-version: '5.0'
-#     topology: standalone
-#     app-tests: yes
-#     rails: ['6.0']
-#     os: ubuntu-18.04
-#   display_name: "app tests ${driver}, ${jruby}"
-#   tasks:
-#      - name: "test"
+- matrix_name: app-tests-jruby
+  matrix_spec:
+    jruby: ["jruby-9.3"]
+    driver: ["current"]
+    mongodb-version: '5.0'
+    topology: standalone
+    app-tests: yes
+    rails: ['6.0']
+    os: ubuntu-18.04
+  display_name: "app tests ${driver}, ${jruby}"
+  tasks:
+     - name: "test"

spec/integration/app_spec.rb

@@ -90,7 +90,12 @@ def start_app(cmd, port, timeout)
     end
 
     # Exit should be either success or SIGTERM
-    [0, 15, 128 + 15].should include(status)
+    allowed_statuses = [0, 15, 128 + 15]
+    if RUBY_PLATFORM == 'java'
+      # Puma on JRuby exits with status 1 when it receives a TERM signal.
+      allowed_statuses << 1
+    end
+    allowed_statuses.should include(status)
 
     rv
   end