Add test that replicates parallel problem in issue 285

sqlmock_test.go

diff --git a/sqlmock_test.go b/sqlmock_test.go
index ee6b516..bac72c3 100644
--- a/sqlmock_test.go
+++ b/sqlmock_test.go
@@ -394,6 +394,50 @@
 	}
 }
 
+func TestParallelPreparedQueryExecutions(t *testing.T) {
+	db, mock, err := New()
+	if err != nil {
+		t.Errorf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	mock.MatchExpectationsInOrder(false)
+
+	mock.ExpectPrepare("INSERT INTO authors \\((.+)\\) VALUES \\((.+)\\)").
+		ExpectExec().
+		WithArgs(1, "Jane Doe").
+		WillReturnResult(NewResult(1, 1))
+
+	mock.ExpectPrepare("INSERT INTO authors \\((.+)\\) VALUES \\((.+)\\)").
+		ExpectExec().
+		WithArgs(0, "John Doe").
+		WillReturnResult(NewResult(0, 1))
+
+	t.Run("Parallel1", func(t *testing.T) {
+		t.Parallel()
+
+		stmt, err := db.Prepare("INSERT INTO authors (id, name) VALUES (?, ?)")
+		if err != nil {
+			t.Errorf("error '%s' was not expected while creating a prepared statement", err)
+		} else {
+			_, err = stmt.Exec(0, "John Doe")
+		}
+	})
+
+	t.Run("Parallel2", func(t *testing.T) {
+		t.Parallel()
+
+		stmt, err := db.Prepare("INSERT INTO authors (id, name) VALUES (?, ?)")
+		if err != nil {
+			t.Errorf("error '%s' was not expected while creating a prepared statement", err)
+		} else {
+			_, err = stmt.Exec(1, "Jane Doe")
+		}
+	})
+
+	t.Cleanup(func() {
+		db.Close()
+	})
+}
+
 func TestUnexpectedOperations(t *testing.T) {
 	t.Parallel()
 	db, mock, err := New()
@@ -632,6 +676,89 @@
 	// note this line is important for unordered expectation matching
 	mock.MatchExpectationsInOrder(false)
 
+	data := []interface{}{
+		1,
+		"John Doe",
+		2,
+		"Jane Doe",
+	}
+	rows := NewRows([]string{"id", "name"})
+	rows.AddRow(data[0], data[1])
+	rows.AddRow(data[2], data[3])
+
+	mock.ExpectExec("DROP TABLE IF EXISTS author").WillReturnResult(NewResult(0, 0))
+	mock.ExpectExec("TRUNCATE TABLE").WillReturnResult(NewResult(0, 0))
+
+	mock.ExpectExec("CREATE TABLE IF NOT EXISTS author").WillReturnResult(NewResult(0, 0))
+
+	mock.ExpectQuery("SELECT").WillReturnRows(rows).WithArgs()
+
+	mock.ExpectPrepare("INSERT INTO").
+		ExpectExec().
+		WithArgs(
+			data[0],
+			data[1],
+			data[2],
+			data[3],
+		).
+		WillReturnResult(NewResult(0, 2))
+
+	var wg sync.WaitGroup
+	queries := []func() error{
+		func() error {
+			_, err := db.Exec("CREATE TABLE IF NOT EXISTS author (a varchar(255)")
+			return err
+		},
+		func() error {
+			_, err := db.Exec("TRUNCATE TABLE author")
+			return err
+		},
+		func() error {
+			stmt, err := db.Prepare("INSERT INTO author (id,name) VALUES (?,?),(?,?)")
+			if err != nil {
+				return err
+			}
+			_, err = stmt.Exec(1, "John Doe", 2, "Jane Doe")
+			return err
+		},
+		func() error {
+			_, err := db.Query("SELECT * FROM author")
+			return err
+		},
+		func() error {
+			_, err := db.Exec("DROP TABLE IF EXISTS author")
+			return err
+		},
+	}
+
+	wg.Add(len(queries))
+	for _, f := range queries {
+		go func(f func() error) {
+			if err := f(); err != nil {
+				t.Errorf("error was not expected: %s", err)
+			}
+			wg.Done()
+		}(f)
+	}
+
+	wg.Wait()
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}
+
+func TestGoroutineExecutionMultiTypes(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Errorf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	// note this line is important for unordered expectation matching
+	mock.MatchExpectationsInOrder(false)
+
 	result := NewResult(1, 1)
 
 	mock.ExpectExec("^UPDATE one").WithArgs("one").WillReturnResult(result)