Improve drone

.drone.yml

@@ -19,7 +19,6 @@ steps:
   environment:
     GO111MODULE: "on"
     GOPROXY: "https://goproxy.cn"
-    TEST_CACHE_ENABLE: false
   commands:
   - make test-sqlite
   - TEST_CACHE_ENABLE=true make test-sqlite
@@ -38,12 +37,29 @@ steps:
     TEST_MYSQL_DBNAME: xorm_test
     TEST_MYSQL_USERNAME: root
     TEST_MYSQL_PASSWORD:
-    TEST_CACHE_ENABLE: false
   commands:
   - make test-mysql
   - TEST_CACHE_ENABLE=true make test-mysql
-  - TEST_MYSQL_CHARSET=utf8mb4 make test-mysql
-  - TEST_MYSQL_CHARSET=utf8mb4 TEST_CACHE_ENABLE=true make test-mysql
+  when:
+    event:
+    - push
+    - pull_request
+
+- name: test-mysql-utf8mb4
+  image: golang:1.12
+  depends_on:
+  - test-mysql
+  environment:
+    GO111MODULE: "on"
+    GOPROXY: "https://goproxy.cn"
+    TEST_MYSQL_HOST: mysql
+    TEST_MYSQL_CHARSET: utf8mb4
+    TEST_MYSQL_DBNAME: xorm_test
+    TEST_MYSQL_USERNAME: root
+    TEST_MYSQL_PASSWORD:
+  commands:
+  - make test-mysql
+  - TEST_CACHE_ENABLE=true make test-mysql
   when:
     event:
     - push
@@ -90,6 +106,8 @@ steps:
 - name: test-postgres-schema
   pull: default
   image: golang:1.12
+  depends_on:
+  - test-postgres
   environment:
     GO111MODULE: "on"
     GOPROXY: "https://goproxy.cn"