pool: Leave failed postgres db state in pool tests.

This modifies the pool tests to avoid cleaning up the postgres data when
there is a test failure so the contents of the database can be examined.

Since a failed run will no longer purge the data, it also adds log to
purge the data prior to running the tests to ensure any previous failed
runs are cleaned up on subsequent runs.

pool/pool_test.go

@@ -132,6 +132,17 @@ func TestPool(t *testing.T) {
 		boltDB.Close()
 	}
 
+	// Cleanup postgres DB from potential failed previous runs.
+	postgresDB, err := setupPostgresDB()
+	if err != nil {
+		t.Fatalf("setupPostgresDB error: %v", err)
+	}
+	err = postgresDB.purge()
+	if err != nil {
+		t.Fatalf("postgres teardown error: %v", err)
+	}
+	postgresDB.Close()
+
 	// Run all tests with postgres DB.
 	for testName, test := range tests {
 		if t.Failed() {
@@ -147,9 +158,11 @@ func TestPool(t *testing.T) {
 
 		t.Run(testName+"_Postgres", test)
 
-		err = postgresDB.purge()
-		if err != nil {
-			t.Fatalf("postgres teardown error: %v", err)
+		if !t.Failed() {
+			err = postgresDB.purge()
+			if err != nil {
+				t.Fatalf("postgres teardown error: %v", err)
+			}
 		}
 
 		postgresDB.Close()