Breaking Change: changes the Exec() signature so it returns an extra value

The signature was updated from

- `Exec(...) (rowsAffected int64, _ error)`

To:

- `Exec(...) (ksql.Result, error)`

Result is an interface, so it should be easy to mock, we are also
providing a new builtin mock struct + constructor to make it even easier:

Building new mock Result: `ksql.NewMockResult(lastInsertID int64, rowsAffected int64) Result`

contracts.go

@@ -30,7 +30,7 @@ type Provider interface {
 	QueryOne(ctx context.Context, record interface{}, query string, params ...interface{}) error
 	QueryChunks(ctx context.Context, parser ChunkParser) error
 
-	Exec(ctx context.Context, query string, params ...interface{}) (rowsAffected int64, _ error)
+	Exec(ctx context.Context, query string, params ...interface{}) (Result, error)
 	Transaction(ctx context.Context, fn func(Provider) error) error
 }
 

examples/example_service/mocks.go

@@ -50,14 +50,14 @@ func (mr *MockProviderMockRecorder) Delete(ctx, table, idOrRecord interface{}) *
 }
 
 // Exec mocks base method.
-func (m *MockProvider) Exec(ctx context.Context, query string, params ...interface{}) (int64, error) {
+func (m *MockProvider) Exec(ctx context.Context, query string, params ...interface{}) (ksql.Result, error) {
 	m.ctrl.T.Helper()
 	varargs := []interface{}{ctx, query}
 	for _, a := range params {
 		varargs = append(varargs, a)
 	}
 	ret := m.ctrl.Call(m, "Exec", varargs...)
-	ret0, _ := ret[0].(int64)
+	ret0, _ := ret[0].(ksql.Result)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }

ksql.go

@@ -839,10 +839,8 @@ func buildUpdateQuery(
 }
 
 // Exec just runs an SQL command on the database returning no rows.
-func (c DB) Exec(ctx context.Context, query string, params ...interface{}) (rowsAffected int64, _ error) {
-	result, err := c.db.ExecContext(ctx, query, params...)
-	rowsAffected, _ = result.RowsAffected()
-	return rowsAffected, err
+func (c DB) Exec(ctx context.Context, query string, params ...interface{}) (Result, error) {
+	return c.db.ExecContext(ctx, query, params...)
 }
 
 // Transaction just runs an SQL command on the database returning no rows.

mocks.go

@@ -59,10 +59,22 @@ type Mock struct {
 	QueryOneFn    func(ctx context.Context, record interface{}, query string, params ...interface{}) error
 	QueryChunksFn func(ctx context.Context, parser ChunkParser) error
 
-	ExecFn        func(ctx context.Context, query string, params ...interface{}) (rowsAffected int64, _ error)
+	ExecFn        func(ctx context.Context, query string, params ...interface{}) (Result, error)
 	TransactionFn func(ctx context.Context, fn func(db Provider) error) error
 }
 
+// MockResult implements the Result interface returned by the Exec function
+//
+// Use the constructor `NewMockResult(42, 42)` for a simpler instantiation of this mock.
+//
+// But if you want one of the functions to return an error you'll need
+// to specify the desired behavior by overwriting one of the attributes
+// of the struct.
+type MockResult struct {
+	LastInsertIdFn func() (int64, error)
+	RowsAffectedFn func() (int64, error)
+}
+
 // SetFallbackDatabase will set all the Fn attributes to use
 // the function from the input database.
 //
@@ -197,7 +209,7 @@ func (m Mock) QueryChunks(ctx context.Context, parser ChunkParser) error {
 // Exec mocks the behavior of the Exec method.
 // If ExecFn is set it will just call it returning the same return values.
 // If ExecFn is unset it will panic with an appropriate error message.
-func (m Mock) Exec(ctx context.Context, query string, params ...interface{}) (rowsAffected int64, _ error) {
+func (m Mock) Exec(ctx context.Context, query string, params ...interface{}) (Result, error) {
 	if m.ExecFn == nil {
 		panic(fmt.Errorf("ksql.Mock.Exec(ctx, %s, %v) called but the ksql.Mock.ExecFn() is not set", query, params))
 	}
@@ -214,3 +226,27 @@ func (m Mock) Transaction(ctx context.Context, fn func(db Provider) error) error
 	}
 	return m.TransactionFn(ctx, fn)
 }
+
+// NewMockResult returns a simple implementation of the Result interface.
+func NewMockResult(lastInsertID int64, rowsAffected int64) Result {
+	return MockResult{
+		LastInsertIdFn: func() (int64, error) { return lastInsertID, nil },
+		RowsAffectedFn: func() (int64, error) { return rowsAffected, nil },
+	}
+}
+
+// LastInsertId implements the Result interface
+func (m MockResult) LastInsertId() (int64, error) {
+	if m.LastInsertIdFn == nil {
+		panic(fmt.Errorf("ksql.MockResult.LastInsertId() called but ksql.MockResult.LastInsertIdFn is not set"))
+	}
+	return m.LastInsertIdFn()
+}
+
+// RowsAffected implements the Result interface
+func (m MockResult) RowsAffected() (int64, error) {
+	if m.RowsAffectedFn == nil {
+		panic(fmt.Errorf("ksql.MockResult.RowsAffected() called but ksql.MockResult.RowsAffectedFn is not set"))
+	}
+	return m.RowsAffectedFn()
+}

mocks_test.go

@@ -383,17 +383,22 @@ func TestMock(t *testing.T) {
 				params []interface{}
 			}
 			mock := ksql.Mock{
-				ExecFn: func(ctx context.Context, query string, params ...interface{}) (rowsAffected int64, _ error) {
+				ExecFn: func(ctx context.Context, query string, params ...interface{}) (ksql.Result, error) {
 					capturedArgs.ctx = ctx
 					capturedArgs.query = query
 					capturedArgs.params = params
-					return 42, fmt.Errorf("fake-error")
+					return ksql.NewMockResult(42, 42), fmt.Errorf("fake-error")
 				},
 			}
-			rowsAffected, err := mock.Exec(ctx, "INSERT INTO users_permissions(user_id, permission_id) VALUES (?, ?)", 4242, 4)
+			r, err := mock.Exec(ctx, "INSERT INTO users_permissions(user_id, permission_id) VALUES (?, ?)", 4242, 4)
 
 			tt.AssertErrContains(t, err, "fake-error")
+			rowsAffected, err := r.RowsAffected()
+			tt.AssertNoErr(t, err)
 			tt.AssertEqual(t, rowsAffected, int64(42))
+			lastInsertID, err := r.LastInsertId()
+			tt.AssertNoErr(t, err)
+			tt.AssertEqual(t, lastInsertID, int64(42))
 			tt.AssertEqual(t, capturedArgs.ctx, ctx)
 			tt.AssertEqual(t, capturedArgs.query, "INSERT INTO users_permissions(user_id, permission_id) VALUES (?, ?)")
 			tt.AssertEqual(t, capturedArgs.params, []interface{}{4242, 4})
@@ -441,8 +446,8 @@ func TestMock(t *testing.T) {
 			QueryChunksFn: func(ctx context.Context, parser ksql.ChunkParser) error {
 				return fmt.Errorf("called from QueryChunksFn")
 			},
-			ExecFn: func(ctx context.Context, query string, params ...interface{}) (rowsAffected int64, _ error) {
-				return 0, fmt.Errorf("called from ExecFn")
+			ExecFn: func(ctx context.Context, query string, params ...interface{}) (ksql.Result, error) {
+				return nil, fmt.Errorf("called from ExecFn")
 			},
 			TransactionFn: func(ctx context.Context, fn func(db ksql.Provider) error) error {
 				return fmt.Errorf("called from TransactionFn")