allow to set errors for rows scan

* 9a36c2e more examples and tests for rows
* 908877e cannot mock rows.Columns error so far

expectations_test.go

@@ -2,6 +2,7 @@ package sqlmock
 
 import (
 	"database/sql/driver"
+	"fmt"
 	"regexp"
 	"testing"
 	"time"
@@ -71,3 +72,13 @@ func TestQueryExpectationSqlMatch(t *testing.T) {
 		t.Errorf("Sql must have matched the query")
 	}
 }
+
+func ExampleExpectExec() {
+	db, mock, _ := New()
+	result := NewErrorResult(fmt.Errorf("some error"))
+	mock.ExpectExec("^INSERT (.+)").WillReturnResult(result)
+	res, _ := db.Exec("INSERT something")
+	_, err := res.LastInsertId()
+	fmt.Println(err)
+	// Output: some error
+}

result_test.go

@@ -9,14 +9,21 @@ import (
 var mock = &Sqlmock{}
 
 func ExampleNewErrorResult() {
+	db, mock, _ := New()
 	result := NewErrorResult(fmt.Errorf("some error"))
 	mock.ExpectExec("^INSERT (.+)").WillReturnResult(result)
+	res, _ := db.Exec("INSERT something")
+	_, err := res.LastInsertId()
+	fmt.Println(err)
+	// Output: some error
 }
 
 func ExampleNewResult() {
 	var lastInsertID, affected int64
 	result := NewResult(lastInsertID, affected)
 	mock.ExpectExec("^INSERT (.+)").WillReturnResult(result)
+	fmt.Println(mock.ExpectationsWereMet())
+	// Output: there is a remaining expectation *sqlmock.ExpectedExec which was not matched yet
 }
 
 func TestShouldReturnValidSqlDriverResult(t *testing.T) {

rows.go

@@ -17,19 +17,35 @@ type Rows interface {
 	// return the same instance to perform subsequent actions.
 	// Note that the number of values must match the number
 	// of columns
-	AddRow(...driver.Value) Rows
+	AddRow(columns ...driver.Value) Rows
 
 	// FromCSVString build rows from csv string.
 	// return the same instance to perform subsequent actions.
 	// Note that the number of values must match the number
 	// of columns
 	FromCSVString(s string) Rows
+
+	// RowError allows to set an error
+	// which will be returned when a given
+	// row number is read
+	RowError(row int, err error) Rows
+
+	// CloseError allows to set an error
+	// which will be returned by rows.Close
+	// function.
+	//
+	// The close error will be triggered only in cases
+	// when rows.Next() EOF was not yet reached, that is
+	// a default sql library behavior
+	CloseError(err error) Rows
 }
 
 type rows struct {
-	cols []string
-	rows [][]driver.Value
-	pos  int
+	cols     []string
+	rows     [][]driver.Value
+	pos      int
+	scanErr  map[int]error
+	closeErr error
 }
 
 func (r *rows) Columns() []string {
@@ -37,11 +53,7 @@ func (r *rows) Columns() []string {
 }
 
 func (r *rows) Close() error {
-	return nil
-}
-
-func (r *rows) Err() error {
-	return nil
+	return r.closeErr
 }
 
 // advances to next row
@@ -55,14 +67,24 @@ func (r *rows) Next(dest []driver.Value) error {
 		dest[i] = col
 	}
 
-	return nil
+	return r.scanErr[r.pos-1]
 }
 
 // NewRows allows Rows to be created from a
 // sql driver.Value slice or from the CSV string and
 // to be used as sql driver.Rows
 func NewRows(columns []string) Rows {
-	return &rows{cols: columns}
+	return &rows{cols: columns, scanErr: make(map[int]error)}
+}
+
+func (r *rows) CloseError(err error) Rows {
+	r.closeErr = err
+	return r
+}
+
+func (r *rows) RowError(row int, err error) Rows {
+	r.scanErr[row] = err
+	return r
 }
 
 func (r *rows) AddRow(values ...driver.Value) Rows {

rows_test.go

@@ -0,0 +1,209 @@
+package sqlmock
+
+import (
+	"database/sql"
+	"fmt"
+	"testing"
+)
+
+func ExampleRows() {
+	db, mock, err := New()
+	if err != nil {
+		fmt.Println("failed to open sqlmock database:", err)
+	}
+	defer db.Close()
+
+	rows := NewRows([]string{"id", "title"}).
+		AddRow(1, "one").
+		AddRow(2, "two")
+
+	mock.ExpectQuery("SELECT").WillReturnRows(rows)
+
+	rs, _ := db.Query("SELECT")
+	defer rs.Close()
+
+	for rs.Next() {
+		var id int
+		var title string
+		rs.Scan(&id, &title)
+		fmt.Println("scanned id:", id, "and title:", title)
+	}
+
+	if rs.Err() != nil {
+		fmt.Println("got rows error:", rs.Err())
+	}
+	// Output: scanned id: 1 and title: one
+	// scanned id: 2 and title: two
+}
+
+func ExampleRows_rowError() {
+	db, mock, err := New()
+	if err != nil {
+		fmt.Println("failed to open sqlmock database:", err)
+	}
+	defer db.Close()
+
+	rows := NewRows([]string{"id", "title"}).
+		AddRow(0, "one").
+		AddRow(1, "two").
+		RowError(1, fmt.Errorf("row error"))
+	mock.ExpectQuery("SELECT").WillReturnRows(rows)
+
+	rs, _ := db.Query("SELECT")
+	defer rs.Close()
+
+	for rs.Next() {
+		var id int
+		var title string
+		rs.Scan(&id, &title)
+		fmt.Println("scanned id:", id, "and title:", title)
+	}
+
+	if rs.Err() != nil {
+		fmt.Println("got rows error:", rs.Err())
+	}
+	// Output: scanned id: 0 and title: one
+	// got rows error: row error
+}
+
+func ExampleRows_closeError() {
+	db, mock, err := New()
+	if err != nil {
+		fmt.Println("failed to open sqlmock database:", err)
+	}
+	defer db.Close()
+
+	rows := NewRows([]string{"id", "title"}).CloseError(fmt.Errorf("close error"))
+	mock.ExpectQuery("SELECT").WillReturnRows(rows)
+
+	rs, _ := db.Query("SELECT")
+
+	// Note: that close will return error only before rows EOF
+	// that is a default sql package behavior. If you run rs.Next()
+	// it will handle the error internally and return nil bellow
+	if err := rs.Close(); err != nil {
+		fmt.Println("got error:", err)
+	}
+
+	// Output: got error: close error
+}
+
+func TestAllowsToSetRowsErrors(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	rows := NewRows([]string{"id", "title"}).
+		AddRow(0, "one").
+		AddRow(1, "two").
+		RowError(1, fmt.Errorf("error"))
+	mock.ExpectQuery("SELECT").WillReturnRows(rows)
+
+	rs, err := db.Query("SELECT")
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	defer rs.Close()
+
+	if !rs.Next() {
+		t.Fatal("expected the first row to be available")
+	}
+	if rs.Err() != nil {
+		t.Fatalf("unexpected error: %s", rs.Err())
+	}
+
+	if rs.Next() {
+		t.Fatal("was not expecting the second row, since there should be an error")
+	}
+	if rs.Err() == nil {
+		t.Fatal("expected an error, but got none")
+	}
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestRowsCloseError(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	rows := NewRows([]string{"id"}).CloseError(fmt.Errorf("close error"))
+	mock.ExpectQuery("SELECT").WillReturnRows(rows)
+
+	rs, err := db.Query("SELECT")
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	if err := rs.Close(); err == nil {
+		t.Fatal("expected a close error")
+	}
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestQuerySingleRow(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	rows := NewRows([]string{"id"}).
+		AddRow(1).
+		AddRow(2)
+	mock.ExpectQuery("SELECT").WillReturnRows(rows)
+
+	var id int
+	if err := db.QueryRow("SELECT").Scan(&id); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	mock.ExpectQuery("SELECT").WillReturnRows(NewRows([]string{"id"}))
+	if err := db.QueryRow("SELECT").Scan(&id); err != sql.ErrNoRows {
+		t.Fatal("expected sql no rows error")
+	}
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// @TODO: the only way to mock columns error would be
+// to return nil instead of rows, but rows.Close will
+// panic due to a bug in go sql package
+func TODO_TestRowsColumnsError(t *testing.T) {
+	t.Parallel()
+	db, mock, err := New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	mock.ExpectQuery("SELECT").WillReturnRows(nil)
+
+	rs, err := db.Query("SELECT")
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	_, err = rs.Columns()
+	if err == nil {
+		t.Fatal("expected an error for columns")
+	}
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}

sqlmock.go

@@ -201,6 +201,7 @@ func (c *Sqlmock) Query(query string, args []driver.Value) (rw driver.Rows, err
 		return nil, t.err // mocked to return error
 	}
 
+	// remove when rows_test.go:186 is available, won't cause a BC
 	if t.rows == nil {
 		return nil, fmt.Errorf("query '%s' with args %+v, must return a database/sql/driver.rows, but it was not set for expectation %T as %+v", query, args, t, t)
 	}