Adjust Travis build environments - fixes #2861 (#2866)

* Adjust Travis build environments - fixes #2861

Fixes #2861
- Only builds one each of JDK 11-14
- Fixes all validator warnings
- Switches default build environment to bionic
- Uses trusty for an Oracle JDK 8 build
- Adds OS X build
- Adds JDK 13 & 14 builds
- Adds placeholder for JDK 16 builds
  (but Jacoco doesn't currently support it,
   so commented out)
- Reorder build jobs so that most informative ones run first
- Split before_install into before_install and
  before_script sections

* Drop redundant JDK 13 build

* Swap OS X to JDK 14 instead of JDK 13

This doesn't have anything to do with JDK or OS X versions,
but instead the Travis CI build images. A bug in the homebrew
support was only fixed in recent images, so we need to use
an xcode11 build which implies macOS 10.14 or 10.5 and
JDK 14 or 14.0.1.

.travis.yml

@@ -1,10 +1,47 @@
+os: linux
 language: java
-dist: xenial
-jdk:
-  - openjdk8
-  - oraclejdk11
-  - openjdk11
-  - openjdk12
+dist: bionic
+
+jobs:
+  include:
+    - dist: trusty # Fastest build first
+      jdk: oraclejdk8
+    - jdk: openjdk13
+    - jdk: oraclejdk11
+    - os: osx
+      osx_image: xcode11.6 # macOS 10.15.4, Oracle JDK 14.0.1
+      language: java
+      services: # not supported on os x
+      addons:
+        homebrew:
+          packages:
+            - mysql
+            - mariadb@10.3
+      before_script:
+        - brew services start mysql
+        - brew services start postgresql
+        - brew services start mariadb@10.3
+        #- sleep 15 # wait for databases to start up
+        # Homebrew postgres workaround - create expected user postgres
+        - /usr/local/opt/postgres/bin/createuser -s postgres
+        # FIXME this is duplicated from linux config, but don't know a better way to do it
+        - mysql -u root -e 'CREATE DATABASE test_db;'
+        - mysql -u root test_db < extensions/database/tests/conf/travis-mysql.sql
+        - psql -c 'CREATE DATABASE test_db;' -U postgres
+        - psql -U postgres test_db < extensions/database/tests/conf/travis-pgsql.sql
+        - cp extensions/database/tests/conf/travis_tests.xml extensions/database/tests/conf/tests.xml
+    - jdk: openjdk12
+      dist: xenial # just for a little variety
+# Jacoco doesn't work with Java 16 and this workaround doesn't work
+#    - jdk: oraclejdk-ea
+#      script: mvn test
+#      after_success: mvn prepare-package -DskipTests=true
+#    - jdk: openjdk-ea
+#      script: mvn test
+#      after_success: mvn prepare-package -DskipTests=true
+  allow_failures:
+    - jdk: openjdk-ea
+    - jdk: oraclejdk-ea
 
 addons:
   mariadb: '10.3'
@@ -18,14 +55,17 @@ env:
   - secure: "VmS4He99YlI6rdmw8Q25OZ9kUp11sRbt0W1QMBvA5lzNSmhN1Q1KtaMj9AGwpCZWcyGWri4AQxEmloARxACxQHXRmNE7ro2DESGw46RAocBAf+RfBxYTifIyUGu5TnSCQhz56SkgpyWpedZAZWyah9ZxgUMfet4KXFUfeiUgYQA="
   
 before_install:
-  # create test database for mysql, mariadb and postgresql
+  # Fake out packaging for Travis builds before mvn install
+  - cp packaging/travis_pom.xml packaging/pom.xml
+  - mvn process-resources
+
+before_script:
+  # create test databases for mysql, mariadb and postgresql
   - mysql -u root -e 'CREATE DATABASE test_db;'
   - mysql -u root test_db < extensions/database/tests/conf/travis-mysql.sql
   - psql -c 'CREATE DATABASE test_db;' -U postgres
   - psql -U postgres test_db < extensions/database/tests/conf/travis-pgsql.sql
   - cp extensions/database/tests/conf/travis_tests.xml extensions/database/tests/conf/tests.xml
-  - cp packaging/travis_pom.xml packaging/pom.xml
-  - mvn process-resources
 
 script:
   - mvn jacoco:prepare-agent test