test-driver (#93)

Author: scottlepp

datasource.go

@@ -176,7 +176,6 @@ func (ds *SQLDatasource) getDBConnectionFromQuery(q *Query, datasourceUID string
 		return key, cachedConn, nil
 	}
 
-	var err error
 	db, err := ds.c.Connect(dbConn.settings, q.ConnectionArgs)
 	if err != nil {
 		return "", dbConnection{}, err

test/driver.go

@@ -0,0 +1,161 @@
+package test
+
+import (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"io"
+	"reflect"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data/sqlutil"
+	"github.com/grafana/sqlds/v2"
+	"github.com/grafana/sqlds/v2/mock"
+)
+
+var registered = map[string]*SqlHandler{}
+
+// NewDriver creates and registers a new test datasource driver
+func NewDriver(name string, dbdata Data, converters []sqlutil.Converter, opts DriverOpts) (TestDS, *SqlHandler) {
+	if registered[name] == nil {
+		handler := NewDriverHandler(dbdata, opts)
+		registered[name] = &handler
+		mock.RegisterDriver(name, &handler)
+	}
+
+	return NewTestDS(
+		func() (*sql.DB, error) {
+			return sql.Open(name, "")
+		},
+		converters,
+	), registered[name]
+}
+
+// NewTestDS creates a new test datasource driver
+func NewTestDS(openDBfn func() (*sql.DB, error), converters []sqlutil.Converter) TestDS {
+	return TestDS{
+		openDBfn:   openDBfn,
+		converters: converters,
+	}
+}
+
+// NewDriverHandler creates a new driver handler
+func NewDriverHandler(data Data, opts DriverOpts) SqlHandler {
+	return SqlHandler{
+		Data: data,
+		Opts: opts,
+	}
+}
+
+// SqlHandler handles driver functions
+type SqlHandler struct {
+	mock.DBHandler
+	Data  Data
+	Opts  DriverOpts
+	State State
+	row   int
+}
+
+// Ping represents a database ping
+func (s *SqlHandler) Ping(ctx context.Context) error {
+	s.State.ConnectAttempts += 1
+	if s.Opts.ConnectDelay > 0 {
+		time.Sleep(time.Duration(s.Opts.ConnectDelay * int(time.Second))) // simulate a connection delay
+	}
+	if s.Opts.ConnectError != nil {
+		return s.Opts.ConnectError
+	}
+	return nil
+}
+
+// Query represents a database query
+func (s *SqlHandler) Query(args []driver.Value) (driver.Rows, error) {
+	s.State.QueryAttempts += 1
+	if s.Opts.QueryDelay > 0 {
+		time.Sleep(time.Duration(s.Opts.QueryDelay * int(time.Second))) // simulate a query delay
+	}
+	s.row = 0
+	if s.Opts.QueryError != nil {
+		return s, s.Opts.QueryError
+	}
+	return s, nil
+}
+
+// Columns represents columns from a query
+func (s *SqlHandler) Columns() []string {
+	var cols []string
+	for _, c := range s.Data.Cols {
+		cols = append(cols, c.Name)
+	}
+	return cols
+}
+
+// Next iterates over rows
+func (s *SqlHandler) Next(dest []driver.Value) error {
+	if s.row+1 > len(s.Data.Rows) {
+		return io.EOF
+	}
+
+	s.row++
+	for _, row := range s.Data.Rows {
+		for i, col := range row {
+			dest[i] = col
+		}
+	}
+	return nil
+}
+
+// Close implements the database Close interface
+func (s SqlHandler) Close() error {
+	return nil
+}
+
+// ColumnTypeScanType returns the scan type for the column
+func (s SqlHandler) ColumnTypeScanType(index int) reflect.Type {
+	kind := s.Data.Cols[index].Kind
+	return reflect.TypeOf(kind)
+}
+
+// ColumnTypeDatabaseTypeName returns the database type for the column
+func (s SqlHandler) ColumnTypeDatabaseTypeName(index int) string {
+	return s.Data.Cols[index].DataType
+}
+
+// Data - the columns/rows
+type Data struct {
+	Cols []Column
+	Rows [][]any
+}
+
+// Column - the column meta
+type Column struct {
+	Name     string
+	Kind     any
+	DataType string
+}
+
+// TestDS ...
+type TestDS struct {
+	openDBfn   func() (*sql.DB, error)
+	converters []sqlutil.Converter
+	sqlds.Driver
+}
+
+// Open - opens the test database
+func (s TestDS) Open() (*sql.DB, error) {
+	return s.openDBfn()
+}
+
+// DriverOpts the optional settings
+type DriverOpts struct {
+	ConnectDelay int
+	QueryDelay   int
+	ConnectError error
+	QueryError   error
+}
+
+// State is the state of the connections/queries
+type State struct {
+	QueryAttempts   int
+	ConnectAttempts int
+}