build: execute parallel integration tests (googleapis#797)

Refactors the integration tests to fix a number of problems:
1. Too much state was kept in the abstract base class for all integration tests. This did not work properly with parameterized tests, as some state leaked from one parameter value (dialect) to another.
2. The emulator cannot use an existing instance for testing, as it always starts without any existing instances. This is now fixed by forcing tests to used a separate instance for each test class when running on the emulator, and by fixing creation and database cleanup before/after tests.

In addition the integration tests were not executed by Kokoro, as they were skipped in the default test execution. All integration tests are now executed by default.

@ansh0l @mpeddada1 
The integration tests are (probably) still failing, but that is because the default test instance (projects/gcloud-devel/instances/spanner-testing-east1) is clogged with old (?) test databases that have not been cleaned up. Some test cases therefore currently fail with an error that they cannot create another database, as the max of 100 databases per instance has been reached. I don't have access to the affected instance, so I cannot clean it up. Hopefully one of you has access to it.
I've verified that the integration tests work on a different instance.

pom.xml

@@ -237,35 +237,9 @@
             </spanner.testenv.instance>
           </systemPropertyVariables>
           <forkedProcessTimeoutInSeconds>2400</forkedProcessTimeoutInSeconds>
+          <forkCount>8</forkCount>
+          <reuseForks>true</reuseForks>
         </configuration>
-        <executions>
-          <execution>
-            <id>default</id>
-            <goals>
-              <goal>integration-test</goal>
-            </goals>
-            <configuration>
-              <groups>com.google.cloud.spanner.IntegrationTest</groups>
-              <excludedGroups>
-                com.google.cloud.spanner.FlakyTest,com.google.cloud.spanner.ParallelIntegrationTest
-              </excludedGroups>
-            </configuration>
-          </execution>
-          <execution>
-            <id>parallel-integration-test</id>
-            <goals>
-              <goal>integration-test</goal>
-            </goals>
-            <configuration>
-              <groups>com.google.cloud.spanner.ParallelIntegrationTest</groups>
-              <excludedGroups>
-                com.google.cloud.spanner.FlakyTest,com.google.cloud.spanner.IntegrationTest
-              </excludedGroups>
-              <forkCount>8</forkCount>
-              <reuseForks>true</reuseForks>
-            </configuration>
-          </execution>
-        </executions>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetColumns.sql

@@ -74,7 +74,7 @@ SELECT TABLE_CATALOG AS "TABLE_CAT", TABLE_SCHEMA AS "TABLE_SCHEM", TABLE_NAME A
            ELSE 'YES'
         END AS "IS_GENERATEDCOLUMN"
 FROM INFORMATION_SCHEMA.COLUMNS C
-WHERE UPPER(C.TABLE_CATALOG) LIKE ?
+WHERE UPPER(COALESCE(C.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(C.TABLE_SCHEMA) LIKE ?
   AND UPPER(C.TABLE_NAME) LIKE ?
   AND UPPER(C.COLUMN_NAME) LIKE ?

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetCrossReferences.sql

@@ -20,12 +20,12 @@ SELECT	PARENT.TABLE_CATALOG AS "PKTABLE_CAT", PARENT.TABLE_SCHEMA AS "PKTABLE_SC
           3 AS "DELETE_RULE", CONSTRAINTS.CONSTRAINT_NAME AS "FK_NAME", CONSTRAINTS.UNIQUE_CONSTRAINT_NAME AS "PK_NAME",
           7 AS "DEFERRABILITY"
 FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS CONSTRAINTS
-         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CHILD  ON CONSTRAINTS.CONSTRAINT_CATALOG=CHILD.CONSTRAINT_CATALOG AND CONSTRAINTS.CONSTRAINT_SCHEMA= CHILD.CONSTRAINT_SCHEMA AND CONSTRAINTS.CONSTRAINT_NAME= CHILD.CONSTRAINT_NAME
-         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE PARENT ON CONSTRAINTS.UNIQUE_CONSTRAINT_CATALOG=PARENT.CONSTRAINT_CATALOG AND CONSTRAINTS.UNIQUE_CONSTRAINT_SCHEMA=PARENT.CONSTRAINT_SCHEMA AND CONSTRAINTS.UNIQUE_CONSTRAINT_NAME=PARENT.CONSTRAINT_NAME AND PARENT.ORDINAL_POSITION=CHILD.POSITION_IN_UNIQUE_CONSTRAINT
-WHERE UPPER(PARENT.TABLE_CATALOG) LIKE ?
+         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CHILD  ON COALESCE(CONSTRAINTS.CONSTRAINT_CATALOG, '')=COALESCE(CHILD.CONSTRAINT_CATALOG, '') AND CONSTRAINTS.CONSTRAINT_SCHEMA= CHILD.CONSTRAINT_SCHEMA AND CONSTRAINTS.CONSTRAINT_NAME= CHILD.CONSTRAINT_NAME
+         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE PARENT ON COALESCE(CONSTRAINTS.UNIQUE_CONSTRAINT_CATALOG, '')=COALESCE(PARENT.CONSTRAINT_CATALOG, '') AND CONSTRAINTS.UNIQUE_CONSTRAINT_SCHEMA=PARENT.CONSTRAINT_SCHEMA AND CONSTRAINTS.UNIQUE_CONSTRAINT_NAME=PARENT.CONSTRAINT_NAME AND PARENT.ORDINAL_POSITION=CHILD.POSITION_IN_UNIQUE_CONSTRAINT
+WHERE UPPER(COALESCE(PARENT.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(PARENT.TABLE_SCHEMA) LIKE ?
   AND UPPER(PARENT.TABLE_NAME) LIKE ?
-  AND UPPER(CHILD.TABLE_CATALOG) LIKE ?
+  AND UPPER(COALESCE(CHILD.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(CHILD.TABLE_SCHEMA) LIKE ?
   AND UPPER(CHILD.TABLE_NAME) LIKE ?
 ORDER BY CHILD.TABLE_CATALOG, CHILD.TABLE_SCHEMA, CHILD.TABLE_NAME, CHILD.ORDINAL_POSITION

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetExportedKeys.sql

@@ -23,9 +23,9 @@ SELECT	PARENT.TABLE_CATALOG AS "PKTABLE_CAT", PARENT.TABLE_SCHEMA AS "PKTABLE_SC
           CONSTRAINTS.CONSTRAINT_NAME AS "FK_NAME", CONSTRAINTS.UNIQUE_CONSTRAINT_NAME AS "PK_NAME",
           7 AS "DEFERRABILITY" -- 7 = importedKeyNotDeferrable
 FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS CONSTRAINTS
-         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CHILD  ON CONSTRAINTS.CONSTRAINT_CATALOG=CHILD.CONSTRAINT_CATALOG AND CONSTRAINTS.CONSTRAINT_SCHEMA= CHILD.CONSTRAINT_SCHEMA AND CONSTRAINTS.CONSTRAINT_NAME= CHILD.CONSTRAINT_NAME
-         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE PARENT ON CONSTRAINTS.UNIQUE_CONSTRAINT_CATALOG=PARENT.CONSTRAINT_CATALOG AND CONSTRAINTS.UNIQUE_CONSTRAINT_SCHEMA=PARENT.CONSTRAINT_SCHEMA AND CONSTRAINTS.UNIQUE_CONSTRAINT_NAME=PARENT.CONSTRAINT_NAME AND PARENT.ORDINAL_POSITION=CHILD.POSITION_IN_UNIQUE_CONSTRAINT
-WHERE UPPER(PARENT.TABLE_CATALOG) LIKE ?
+         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CHILD  ON COALESCE(CONSTRAINTS.CONSTRAINT_CATALOG, '')=COALESCE(CHILD.CONSTRAINT_CATALOG, '') AND CONSTRAINTS.CONSTRAINT_SCHEMA= CHILD.CONSTRAINT_SCHEMA AND CONSTRAINTS.CONSTRAINT_NAME= CHILD.CONSTRAINT_NAME
+         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE PARENT ON COALESCE(CONSTRAINTS.UNIQUE_CONSTRAINT_CATALOG, '')=COALESCE(PARENT.CONSTRAINT_CATALOG, '') AND CONSTRAINTS.UNIQUE_CONSTRAINT_SCHEMA=PARENT.CONSTRAINT_SCHEMA AND CONSTRAINTS.UNIQUE_CONSTRAINT_NAME=PARENT.CONSTRAINT_NAME AND PARENT.ORDINAL_POSITION=CHILD.POSITION_IN_UNIQUE_CONSTRAINT
+WHERE UPPER(COALESCE(PARENT.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(PARENT.TABLE_SCHEMA) LIKE ?
   AND UPPER(PARENT.TABLE_NAME) LIKE ?
 ORDER BY CHILD.TABLE_CATALOG, CHILD.TABLE_SCHEMA, CHILD.TABLE_NAME, CHILD.ORDINAL_POSITION

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetImportedKeys.sql

@@ -23,9 +23,9 @@ SELECT	PARENT.TABLE_CATALOG AS "PKTABLE_CAT", PARENT.TABLE_SCHEMA AS "PKTABLE_SC
           CONSTRAINTS.CONSTRAINT_NAME AS "FK_NAME", CONSTRAINTS.UNIQUE_CONSTRAINT_NAME AS "PK_NAME",
           7 AS "DEFERRABILITY" -- 7 = importedKeyNotDeferrable
 FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS CONSTRAINTS
-         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CHILD  ON CONSTRAINTS.CONSTRAINT_CATALOG=CHILD.CONSTRAINT_CATALOG AND CONSTRAINTS.CONSTRAINT_SCHEMA= CHILD.CONSTRAINT_SCHEMA AND CONSTRAINTS.CONSTRAINT_NAME= CHILD.CONSTRAINT_NAME
-         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE PARENT ON CONSTRAINTS.UNIQUE_CONSTRAINT_CATALOG=PARENT.CONSTRAINT_CATALOG AND CONSTRAINTS.UNIQUE_CONSTRAINT_SCHEMA=PARENT.CONSTRAINT_SCHEMA AND CONSTRAINTS.UNIQUE_CONSTRAINT_NAME=PARENT.CONSTRAINT_NAME AND PARENT.ORDINAL_POSITION=CHILD.POSITION_IN_UNIQUE_CONSTRAINT
-WHERE UPPER(CHILD.TABLE_CATALOG) LIKE ?
+         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CHILD  ON COALESCE(CONSTRAINTS.CONSTRAINT_CATALOG, '')=COALESCE(CHILD.CONSTRAINT_CATALOG, '') AND CONSTRAINTS.CONSTRAINT_SCHEMA= CHILD.CONSTRAINT_SCHEMA AND CONSTRAINTS.CONSTRAINT_NAME= CHILD.CONSTRAINT_NAME
+         INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE PARENT ON COALESCE(CONSTRAINTS.UNIQUE_CONSTRAINT_CATALOG, '')=COALESCE(PARENT.CONSTRAINT_CATALOG, '') AND CONSTRAINTS.UNIQUE_CONSTRAINT_SCHEMA=PARENT.CONSTRAINT_SCHEMA AND CONSTRAINTS.UNIQUE_CONSTRAINT_NAME=PARENT.CONSTRAINT_NAME AND PARENT.ORDINAL_POSITION=CHILD.POSITION_IN_UNIQUE_CONSTRAINT
+WHERE UPPER(COALESCE(CHILD.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(CHILD.TABLE_SCHEMA) LIKE ?
   AND UPPER(CHILD.TABLE_NAME) LIKE ?
 ORDER BY PARENT.TABLE_CATALOG, PARENT.TABLE_SCHEMA, PARENT.TABLE_NAME, CHILD.ORDINAL_POSITION

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetIndexInfo.sql

@@ -24,11 +24,11 @@ SELECT IDX.TABLE_CATALOG AS "TABLE_CAT", IDX.TABLE_SCHEMA AS "TABLE_SCHEM", IDX.
        NULL AS "FILTER_CONDITION"
 FROM INFORMATION_SCHEMA.INDEXES IDX
 INNER JOIN INFORMATION_SCHEMA.INDEX_COLUMNS COL
-            ON  IDX.TABLE_CATALOG=COL.TABLE_CATALOG
+            ON  COALESCE(IDX.TABLE_CATALOG, '')=COALESCE(COL.TABLE_CATALOG, '')
                 AND IDX.TABLE_SCHEMA=COL.TABLE_SCHEMA
                 AND IDX.TABLE_NAME=COL.TABLE_NAME
                 AND IDX.INDEX_NAME=COL.INDEX_NAME
-WHERE UPPER(IDX.TABLE_CATALOG) LIKE ?
+WHERE UPPER(COALESCE(IDX.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(IDX.TABLE_SCHEMA) LIKE ?
   AND UPPER(IDX.TABLE_NAME) LIKE ?
   AND UPPER(IDX.INDEX_NAME) LIKE ?

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetPrimaryKeys.sql

@@ -18,12 +18,12 @@ SELECT IDX.TABLE_CATALOG AS "TABLE_CAT", IDX.TABLE_SCHEMA AS "TABLE_SCHEM", IDX.
        COLS.COLUMN_NAME AS "COLUMN_NAME", ORDINAL_POSITION AS "KEY_SEQ", IDX.INDEX_NAME AS "PK_NAME"
 FROM INFORMATION_SCHEMA.INDEXES IDX
 INNER JOIN INFORMATION_SCHEMA.INDEX_COLUMNS COLS
-            ON  IDX.TABLE_CATALOG=COLS.TABLE_CATALOG
+            ON  COALESCE(IDX.TABLE_CATALOG, '')=COALESCE(COLS.TABLE_CATALOG, '')
                 AND IDX.TABLE_SCHEMA=COLS.TABLE_SCHEMA
                 AND IDX.TABLE_NAME=COLS.TABLE_NAME
                 AND IDX.INDEX_NAME=COLS.INDEX_NAME
 WHERE IDX.INDEX_TYPE='PRIMARY_KEY'
-  AND UPPER(IDX.TABLE_CATALOG) LIKE ?
+  AND UPPER(COALESCE(IDX.TABLE_CATALOG, '')) LIKE ?
   AND UPPER(IDX.TABLE_SCHEMA) LIKE ?
   AND UPPER(IDX.TABLE_NAME) LIKE ?
 ORDER BY COLS.ORDINAL_POSITION

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetSchemas.sql

@@ -16,6 +16,6 @@
 
 SELECT SCHEMA_NAME AS "TABLE_SCHEM", CATALOG_NAME AS "TABLE_CATALOG"
 FROM INFORMATION_SCHEMA.SCHEMATA
-WHERE UPPER(CATALOG_NAME) LIKE ?
+WHERE UPPER(COALESCE(CATALOG_NAME, '')) LIKE ?
   AND UPPER(SCHEMA_NAME) LIKE ?
 ORDER BY CATALOG_NAME, SCHEMA_NAME

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetTables.sql

@@ -19,7 +19,7 @@ SELECT TABLE_CATALOG AS "TABLE_CAT", TABLE_SCHEMA AS "TABLE_SCHEM", TABLE_NAME A
        NULL AS "REMARKS", NULL AS "TYPE_CAT", NULL AS "TYPE_SCHEM", NULL AS "TYPE_NAME",
        NULL AS "SELF_REFERENCING_COL_NAME", NULL AS "REF_GENERATION"
 FROM INFORMATION_SCHEMA.TABLES AS T
-WHERE UPPER(TABLE_CATALOG) LIKE ?
+WHERE UPPER(COALESCE(TABLE_CATALOG, '')) LIKE ?
   AND UPPER(TABLE_SCHEMA) LIKE ?
   AND UPPER(TABLE_NAME) LIKE ?
   AND (