mysql_db: Improve tests (#240)

- Define variables "db_names" and "db_formats" in defaults
- Use of the "vars" option in includes instead of default parameters
  that might be overridden by a previous task
- Use of the "loop" option in includes instead of duplicating include
  tasks
- Use a nested loop on db_names and db_formats in state_dump_import test

Signed-off-by: Nicolas Payart <npayart@gmail.com>

tests/integration/targets/test_mysql_db/defaults/main.yml

@@ -4,7 +4,17 @@ mysql_user: root
 mysql_password: msandbox
 mysql_primary_port: 3307
 
-db_name: 'data'
+# Database names
+db_names:
+  - "data"
+  - "db%"
+
+# Database formats
+db_formats:
+  - { format_type: "sql", file: "dbdata.sql", format_msg_type: "ASCII", file2: "dump2.sql", file3: "dump3.sql", file4: "dump4.sql" }
+  - { format_type: "gz",  file: "dbdata.gz",  format_msg_type: "gzip",  file2: "dump2.gz",  file3: "dump3.gz",  file4: "dump4.gz" }
+  - { format_type: "bz2", file: "dbdata.bz2", format_msg_type: "bzip2", file2: "dump2.bz2", file3: "dump3.bz2", file4: "dump4.bz2" }
+
 db_name2: 'data2'
 db_user1: 'datauser1'
 db_user2: 'datauser2'