client: Make example testable

README.md

@@ -190,54 +190,8 @@ You can see [go-mysql-elasticsearch](https://github.com/go-mysql-org/go-mysql-el
 
 Client package supports a simple MySQL connection driver which you can use it to communicate with MySQL server. 
 
-### Example
-
-```go
-import (
-	"github.com/go-mysql-org/go-mysql/client"
-)
-
-// Connect MySQL at 127.0.0.1:3306, with user root, an empty password and database test
-conn, _ := client.Connect("127.0.0.1:3306", "root", "", "test")
-
-// Or to use SSL/TLS connection if MySQL server supports TLS
-//conn, _ := client.Connect("127.0.0.1:3306", "root", "", "test", func(c *Conn) {c.UseSSL(true)})
-
-// Or to set your own client-side certificates for identity verification for security
-//tlsConfig := NewClientTLSConfig(caPem, certPem, keyPem, false, "your-server-name")
-//conn, _ := client.Connect("127.0.0.1:3306", "root", "", "test", func(c *Conn) {c.SetTLSConfig(tlsConfig)})
-
-conn.Ping()
-
-// Insert
-r, _ := conn.Execute(`insert into table (id, name) values (1, "abc")`)
-
-// Get last insert id
-println(r.InsertId)
-// Or affected rows count
-println(r.AffectedRows)
-
-// Select
-r, err := conn.Execute(`select id, name from table where id = 1`)
-
-// Close result for reuse memory (it's not necessary but very useful)
-defer r.Close()
-
-// Handle resultset
-v, _ := r.GetInt(0, 0)
-v, _ = r.GetIntByName(0, "id")
-
-// Direct access to fields
-for _, row := range r.Values {
-	for _, val := range row {
-		_ = val.Value() // interface{}
-		// or
-		if val.Type == mysql.FieldValueTypeFloat {
-			_ = val.AsFloat64() // float64
-		}
-	}   
-}
-```
+For an example see [`example_client_test.go`](client/example_client_test.go). You can run this testable example with 
+`go test -v ./client -run Example`.
 
 Tested MySQL versions for the client include:
 - 5.5.x

client/example_client_test.go

@@ -0,0 +1,111 @@
+package client_test
+
+import (
+	"fmt"
+
+	"github.com/go-mysql-org/go-mysql/client"
+	"github.com/go-mysql-org/go-mysql/mysql"
+)
+
+func Example() {
+	// Connect MySQL at 127.0.0.1:3306, with user root, an empty password and database test
+	conn, err := client.Connect("127.0.0.1:3306", "root", "", "test")
+	// Or to use SSL/TLS connection if MySQL server supports TLS
+	//conn, err := client.Connect("127.0.0.1:3306", "root", "", "test", func(c *Conn) {c.UseSSL(true)})
+
+	// Or to set your own client-side certificates for identity verification for security
+	//tlsConfig := NewClientTLSConfig(caPem, certPem, keyPem, false, "your-server-name")
+	//conn, err := client.Connect("127.0.0.1:3306", "root", "", "test", func(c *Conn) {c.SetTLSConfig(tlsConfig)})
+	if err != nil {
+		msg := fmt.Sprintf(`
+This example needs a MySQL listening on 127.0.0.1:3006 with user "root" and 
+empty password. Please check the connectivity using mysql client.
+---
+Connect to MySQL failed: %v`, err)
+		panic(msg)
+	}
+
+	err = conn.Ping()
+	if err != nil {
+		panic(err)
+	}
+
+	// (re)create the t1 table
+	r, err := conn.Execute(`DROP TABLE IF EXISTS t1`)
+	if err != nil {
+		panic(err)
+	}
+	r.Close()
+	r, err = conn.Execute(`CREATE TABLE t1 (id int PRIMARY KEY, name varchar(255))`)
+	if err != nil {
+		panic(err)
+	}
+	r.Close()
+
+	// Insert
+	r, err = conn.Execute(`INSERT INTO t1(id, name) VALUES(1, "abc"),(2, "def")`)
+	if err != nil {
+		panic(err)
+	}
+	defer r.Close()
+
+	// Get last insert id and number of affected rows
+	fmt.Printf("InsertId: %d, AffectedRows: %d\n", r.InsertId, r.AffectedRows)
+
+	// Select
+	r, err = conn.Execute(`SELECT id, name FROM t1`)
+	if err != nil {
+		panic(err)
+	}
+
+	// Handle resultset
+	v, err := r.GetInt(0, 0)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("Value of Row 0, Column 0: %d\n", v)
+
+	v, err = r.GetIntByName(0, "id")
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("Value of Row 0, Column 'id': %d\n", v)
+
+	// Direct access to fields
+	for rownum, row := range r.Values {
+		fmt.Printf("Row number %d\n", rownum)
+		for colnum, val := range row {
+			fmt.Printf("\tColumn number %d\n", colnum)
+
+			ival := val.Value() // interface{}
+			fmt.Printf("\t\tvalue (type: %d): %#v\n", val.Type, ival)
+
+			if val.Type == mysql.FieldValueTypeSigned {
+				fval := val.AsInt64()
+				fmt.Printf("\t\tint64 value: %d\n", fval)
+			}
+			if val.Type == mysql.FieldValueTypeString {
+				fval := val.AsString()
+				fmt.Printf("\t\tstring value: %s\n", fval)
+			}
+		}
+	}
+	// Output:
+	// InsertId: 0, AffectedRows: 2
+	// Value of Row 0, Column 0: 1
+	// Value of Row 0, Column 'id': 1
+	// Row number 0
+	// 	Column number 0
+	// 		value (type: 2): 1
+	// 		int64 value: 1
+	// 	Column number 1
+	// 		value (type: 4): []byte{0x61, 0x62, 0x63}
+	// 		string value: abc
+	// Row number 1
+	// 	Column number 0
+	// 		value (type: 2): 2
+	// 		int64 value: 2
+	// 	Column number 1
+	// 		value (type: 4): []byte{0x64, 0x65, 0x66}
+	// 		string value: def
+}