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 and the -failfast test flag is set so the
contents of the database can be examined.

Since a failed run with -failfast will no longer purge the data, it also
adds logic 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

@@ -5,6 +5,7 @@
 package pool
 
 import (
+	"flag"
 	"os"
 	"testing"
 
@@ -128,6 +129,17 @@ 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 {
 		postgresDB, err := setupPostgresDB()
@@ -139,9 +151,11 @@ 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() || flag.Lookup("test.failfast") == nil {
+			err = postgresDB.purge()
+			if err != nil {
+				t.Fatalf("postgres teardown error: %v", err)
+			}
 		}
 
 		postgresDB.Close()