sql_test.go

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package sql

import (
	"context"
	"database/sql/driver"
	"errors"
	"fmt"
	"math/rand"
	"reflect"
	"runtime"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	"time"
)

func init() {
	type dbConn struct {
		db *DB
		c  *driverConn
	}
	freedFrom := make(map[dbConn]string)
	var mu sync.Mutex
	getFreedFrom := func(c dbConn) string {
		mu.Lock()
		defer mu.Unlock()
		return freedFrom[c]
	}
	setFreedFrom := func(c dbConn, s string) {
		mu.Lock()
		defer mu.Unlock()
		freedFrom[c] = s
	}
	putConnHook = func(db *DB, c *driverConn) {
		idx := -1
		for i, v := range db.freeConn {
			if v == c {
				idx = i
				break
			}
		}
		if idx >= 0 {
			// print before panic, as panic may get lost due to conflicting panic
			// (all goroutines asleep) elsewhere, since we might not unlock
			// the mutex in freeConn here.
			println("double free of conn. conflicts are:\nA) " + getFreedFrom(dbConn{db, c}) + "\n\nand\nB) " + stack())
			panic("double free of conn.")
		}
		setFreedFrom(dbConn{db, c}, stack())
	}
}

const fakeDBName = "foo"

var chrisBirthday = time.Unix(123456789, 0)

func newTestDB(t testing.TB, name string) *DB {
	db, err := Open("test", fakeDBName)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if _, err := db.Exec("WIPE"); err != nil {
		t.Fatalf("exec wipe: %v", err)
	}
	if name == "people" {
		exec(t, db, "CREATE|people|name=string,age=int32,photo=blob,dead=bool,bdate=datetime")
		exec(t, db, "INSERT|people|name=Alice,age=?,photo=APHOTO", 1)
		exec(t, db, "INSERT|people|name=Bob,age=?,photo=BPHOTO", 2)
		exec(t, db, "INSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?", 3, chrisBirthday)
	}
	if name == "magicquery" {
		// Magic table name and column, known by fakedb_test.go.
		exec(t, db, "CREATE|magicquery|op=string,millis=int32")
		exec(t, db, "INSERT|magicquery|op=sleep,millis=10")
	}
	return db
}

func TestDriverPanic(t *testing.T) {
	// Test that if driver panics, database/sql does not deadlock.
	db, err := Open("test", fakeDBName)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	expectPanic := func(name string, f func()) {
		defer func() {
			err := recover()
			if err == nil {
				t.Fatalf("%s did not panic", name)
			}
		}()
		f()
	}

	expectPanic("Exec Exec", func() { db.Exec("PANIC|Exec|WIPE") })
	exec(t, db, "WIPE") // check not deadlocked
	expectPanic("Exec NumInput", func() { db.Exec("PANIC|NumInput|WIPE") })
	exec(t, db, "WIPE") // check not deadlocked
	expectPanic("Exec Close", func() { db.Exec("PANIC|Close|WIPE") })
	exec(t, db, "WIPE")             // check not deadlocked
	exec(t, db, "PANIC|Query|WIPE") // should run successfully: Exec does not call Query
	exec(t, db, "WIPE")             // check not deadlocked

	exec(t, db, "CREATE|people|name=string,age=int32,photo=blob,dead=bool,bdate=datetime")

	expectPanic("Query Query", func() { db.Query("PANIC|Query|SELECT|people|age,name|") })
	expectPanic("Query NumInput", func() { db.Query("PANIC|NumInput|SELECT|people|age,name|") })
	expectPanic("Query Close", func() {
		rows, err := db.Query("PANIC|Close|SELECT|people|age,name|")
		if err != nil {
			t.Fatal(err)
		}
		rows.Close()
	})
	db.Query("PANIC|Exec|SELECT|people|age,name|") // should run successfully: Query does not call Exec
	exec(t, db, "WIPE")                            // check not deadlocked
}

func exec(t testing.TB, db *DB, query string, args ...interface{}) {
	_, err := db.Exec(query, args...)
	if err != nil {
		t.Fatalf("Exec of %q: %v", query, err)
	}
}

func closeDB(t testing.TB, db *DB) {
	if e := recover(); e != nil {
		fmt.Printf("Panic: %v\n", e)
		panic(e)
	}
	defer setHookpostCloseConn(nil)
	setHookpostCloseConn(func(_ *fakeConn, err error) {
		if err != nil {
			t.Errorf("Error closing fakeConn: %v", err)
		}
	})
	for i, dc := range db.freeConn {
		if n := len(dc.openStmt); n > 0 {
			// Just a sanity check. This is legal in
			// general, but if we make the tests clean up
			// their statements first, then we can safely
			// verify this is always zero here, and any
			// other value is a leak.
			t.Errorf("while closing db, freeConn %d/%d had %d open stmts; want 0", i, len(db.freeConn), n)
		}
	}
	err := db.Close()
	if err != nil {
		t.Fatalf("error closing DB: %v", err)
	}

	var numOpen int
	if !waitCondition(5*time.Second, 5*time.Millisecond, func() bool {
		numOpen = db.numOpenConns()
		return numOpen == 0
	}) {
		t.Fatalf("%d connections still open after closing DB", numOpen)
	}
}

// numPrepares assumes that db has exactly 1 idle conn and returns
// its count of calls to Prepare
func numPrepares(t *testing.T, db *DB) int {
	if n := len(db.freeConn); n != 1 {
		t.Fatalf("free conns = %d; want 1", n)
	}
	return db.freeConn[0].ci.(*fakeConn).numPrepare
}

func (db *DB) numDeps() int {
	db.mu.Lock()
	defer db.mu.Unlock()
	return len(db.dep)
}

// Dependencies are closed via a goroutine, so this polls waiting for
// numDeps to fall to want, waiting up to d.
func (db *DB) numDepsPollUntil(want int, d time.Duration) int {
	deadline := time.Now().Add(d)
	for {
		n := db.numDeps()
		if n <= want || time.Now().After(deadline) {
			return n
		}
		time.Sleep(50 * time.Millisecond)
	}
}

func (db *DB) numFreeConns() int {
	db.mu.Lock()
	defer db.mu.Unlock()
	return len(db.freeConn)
}

func (db *DB) numOpenConns() int {
	db.mu.Lock()
	defer db.mu.Unlock()
	return db.numOpen
}

// clearAllConns closes all connections in db.
func (db *DB) clearAllConns(t *testing.T) {
	db.SetMaxIdleConns(0)

	if g, w := db.numFreeConns(), 0; g != w {
		t.Errorf("free conns = %d; want %d", g, w)
	}

	if n := db.numDepsPollUntil(0, time.Second); n > 0 {
		t.Errorf("number of dependencies = %d; expected 0", n)
		db.dumpDeps(t)
	}
}

func (db *DB) dumpDeps(t *testing.T) {
	for fc := range db.dep {
		db.dumpDep(t, 0, fc, map[finalCloser]bool{})
	}
}

func (db *DB) dumpDep(t *testing.T, depth int, dep finalCloser, seen map[finalCloser]bool) {
	seen[dep] = true
	indent := strings.Repeat("  ", depth)
	ds := db.dep[dep]
	for k := range ds {
		t.Logf("%s%T (%p) waiting for -> %T (%p)", indent, dep, dep, k, k)
		if fc, ok := k.(finalCloser); ok {
			if !seen[fc] {
				db.dumpDep(t, depth+1, fc, seen)
			}
		}
	}
}

func TestQuery(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	prepares0 := numPrepares(t, db)
	rows, err := db.Query("SELECT|people|age,name|")
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	type row struct {
		age  int
		name string
	}
	got := []row{}
	for rows.Next() {
		var r row
		err = rows.Scan(&r.age, &r.name)
		if err != nil {
			t.Fatalf("Scan: %v", err)
		}
		got = append(got, r)
	}
	err = rows.Err()
	if err != nil {
		t.Fatalf("Err: %v", err)
	}
	want := []row{
		{age: 1, name: "Alice"},
		{age: 2, name: "Bob"},
		{age: 3, name: "Chris"},
	}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
	}

	// And verify that the final rows.Next() call, which hit EOF,
	// also closed the rows connection.
	if n := db.numFreeConns(); n != 1 {
		t.Fatalf("free conns after query hitting EOF = %d; want 1", n)
	}
	if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
		t.Errorf("executed %d Prepare statements; want 1", prepares)
	}
}

// TestQueryContext tests canceling the context while scanning the rows.
func TestQueryContext(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	prepares0 := numPrepares(t, db)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	rows, err := db.QueryContext(ctx, "SELECT|people|age,name|")
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	type row struct {
		age  int
		name string
	}
	got := []row{}
	index := 0
	for rows.Next() {
		if index == 2 {
			cancel()
			waitForRowsClose(t, rows, 5*time.Second)
		}
		var r row
		err = rows.Scan(&r.age, &r.name)
		if err != nil {
			if index == 2 {
				break
			}
			t.Fatalf("Scan: %v", err)
		}
		if index == 2 && err == nil {
			t.Fatal("expected an error on last scan")
		}
		got = append(got, r)
		index++
	}
	select {
	case <-ctx.Done():
		if err := ctx.Err(); err != context.Canceled {
			t.Fatalf("context err = %v; want context.Canceled", ctx.Err())
		}
	default:
		t.Fatalf("context err = nil; want context.Canceled")
	}
	want := []row{
		{age: 1, name: "Alice"},
		{age: 2, name: "Bob"},
	}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
	}

	// And verify that the final rows.Next() call, which hit EOF,
	// also closed the rows connection.
	waitForRowsClose(t, rows, 5*time.Second)
	waitForFree(t, db, 5*time.Second, 1)
	if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
		t.Errorf("executed %d Prepare statements; want 1", prepares)
	}
}

func waitCondition(waitFor, checkEvery time.Duration, fn func() bool) bool {
	deadline := time.Now().Add(waitFor)
	for time.Now().Before(deadline) {
		if fn() {
			return true
		}
		time.Sleep(checkEvery)
	}
	return false
}

// waitForFree checks db.numFreeConns until either it equals want or
// the maxWait time elapses.
func waitForFree(t *testing.T, db *DB, maxWait time.Duration, want int) {
	var numFree int
	if !waitCondition(maxWait, 5*time.Millisecond, func() bool {
		numFree = db.numFreeConns()
		return numFree == want
	}) {
		t.Fatalf("free conns after hitting EOF = %d; want %d", numFree, want)
	}
}

func waitForRowsClose(t *testing.T, rows *Rows, maxWait time.Duration) {
	if !waitCondition(maxWait, 5*time.Millisecond, func() bool {
		rows.closemu.RLock()
		defer rows.closemu.RUnlock()
		return rows.closed
	}) {
		t.Fatal("failed to close rows")
	}
}

// TestQueryContextWait ensures that rows and all internal statements are closed when
// a query context is closed during execution.
func TestQueryContextWait(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	prepares0 := numPrepares(t, db)

	// TODO(kardianos): convert this from using a timeout to using an explicit
	// cancel when the query signals that is is "executing" the query.
	ctx, cancel := context.WithTimeout(context.Background(), 300*time.Millisecond)
	defer cancel()

	// This will trigger the *fakeConn.Prepare method which will take time
	// performing the query. The ctxDriverPrepare func will check the context
	// after this and close the rows and return an error.
	_, err := db.QueryContext(ctx, "WAIT|1s|SELECT|people|age,name|")
	if err != context.DeadlineExceeded {
		t.Fatalf("expected QueryContext to error with context deadline exceeded but returned %v", err)
	}

	// Verify closed rows connection after error condition.
	waitForFree(t, db, 5*time.Second, 1)
	if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
		// TODO(kardianos): if the context timeouts before the db.QueryContext
		// executes this check may fail. After adjusting how the context
		// is canceled above revert this back to a Fatal error.
		t.Logf("executed %d Prepare statements; want 1", prepares)
	}
}

// TestTxContextWait tests the transaction behavior when the tx context is canceled
// during execution of the query.
func TestTxContextWait(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)

	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*15)
	defer cancel()

	tx, err := db.BeginTx(ctx, nil)
	if err != nil {
		// Guard against the context being canceled before BeginTx completes.
		if err == context.DeadlineExceeded {
			t.Skip("tx context canceled prior to first use")
		}
		t.Fatal(err)
	}

	// This will trigger the *fakeConn.Prepare method which will take time
	// performing the query. The ctxDriverPrepare func will check the context
	// after this and close the rows and return an error.
	_, err = tx.QueryContext(ctx, "WAIT|1s|SELECT|people|age,name|")
	if err != context.DeadlineExceeded {
		t.Fatalf("expected QueryContext to error with context deadline exceeded but returned %v", err)
	}

	waitForFree(t, db, 5*time.Second, 0)
}

func TestMultiResultSetQuery(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	prepares0 := numPrepares(t, db)
	rows, err := db.Query("SELECT|people|age,name|;SELECT|people|name|")
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	type row1 struct {
		age  int
		name string
	}
	type row2 struct {
		name string
	}
	got1 := []row1{}
	for rows.Next() {
		var r row1
		err = rows.Scan(&r.age, &r.name)
		if err != nil {
			t.Fatalf("Scan: %v", err)
		}
		got1 = append(got1, r)
	}
	err = rows.Err()
	if err != nil {
		t.Fatalf("Err: %v", err)
	}
	want1 := []row1{
		{age: 1, name: "Alice"},
		{age: 2, name: "Bob"},
		{age: 3, name: "Chris"},
	}
	if !reflect.DeepEqual(got1, want1) {
		t.Errorf("mismatch.\n got1: %#v\nwant: %#v", got1, want1)
	}

	if !rows.NextResultSet() {
		t.Errorf("expected another result set")
	}

	got2 := []row2{}
	for rows.Next() {
		var r row2
		err = rows.Scan(&r.name)
		if err != nil {
			t.Fatalf("Scan: %v", err)
		}
		got2 = append(got2, r)
	}
	err = rows.Err()
	if err != nil {
		t.Fatalf("Err: %v", err)
	}
	want2 := []row2{
		{name: "Alice"},
		{name: "Bob"},
		{name: "Chris"},
	}
	if !reflect.DeepEqual(got2, want2) {
		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got2, want2)
	}
	if rows.NextResultSet() {
		t.Errorf("expected no more result sets")
	}

	// And verify that the final rows.Next() call, which hit EOF,
	// also closed the rows connection.
	waitForFree(t, db, 5*time.Second, 1)
	if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
		t.Errorf("executed %d Prepare statements; want 1", prepares)
	}
}

func TestQueryNamedArg(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	prepares0 := numPrepares(t, db)
	rows, err := db.Query(
		// Ensure the name and age parameters only match on placeholder name, not position.
		"SELECT|people|age,name|name=?name,age=?age",
		Named("age", 2),
		Named("name", "Bob"),
	)
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	type row struct {
		age  int
		name string
	}
	got := []row{}
	for rows.Next() {
		var r row
		err = rows.Scan(&r.age, &r.name)
		if err != nil {
			t.Fatalf("Scan: %v", err)
		}
		got = append(got, r)
	}
	err = rows.Err()
	if err != nil {
		t.Fatalf("Err: %v", err)
	}
	want := []row{
		{age: 2, name: "Bob"},
	}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
	}

	// And verify that the final rows.Next() call, which hit EOF,
	// also closed the rows connection.
	if n := db.numFreeConns(); n != 1 {
		t.Fatalf("free conns after query hitting EOF = %d; want 1", n)
	}
	if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
		t.Errorf("executed %d Prepare statements; want 1", prepares)
	}
}

func TestPoolExhaustOnCancel(t *testing.T) {
	if testing.Short() {
		t.Skip("long test")
	}
	db := newTestDB(t, "people")
	defer closeDB(t, db)

	max := 3

	db.SetMaxOpenConns(max)

	// First saturate the connection pool.
	// Then start new requests for a connection that is cancelled after it is requested.

	var saturate, saturateDone sync.WaitGroup
	saturate.Add(max)
	saturateDone.Add(max)

	for i := 0; i < max; i++ {
		go func() {
			saturate.Done()
			rows, err := db.Query("WAIT|500ms|SELECT|people|name,photo|")
			if err != nil {
				t.Fatalf("Query: %v", err)
			}
			rows.Close()
			saturateDone.Done()
		}()
	}

	saturate.Wait()

	// Now cancel the request while it is waiting.
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
	defer cancel()

	for i := 0; i < max; i++ {
		ctxReq, cancelReq := context.WithCancel(ctx)
		go func() {
			time.Sleep(time.Millisecond * 100)
			cancelReq()
		}()
		err := db.PingContext(ctxReq)
		if err != context.Canceled {
			t.Fatalf("PingContext (Exhaust): %v", err)
		}
	}

	saturateDone.Wait()

	// Now try to open a normal connection.
	err := db.PingContext(ctx)
	if err != nil {
		t.Fatalf("PingContext (Normal): %v", err)
	}
}

func TestByteOwnership(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	rows, err := db.Query("SELECT|people|name,photo|")
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	type row struct {
		name  []byte
		photo RawBytes
	}
	got := []row{}
	for rows.Next() {
		var r row
		err = rows.Scan(&r.name, &r.photo)
		if err != nil {
			t.Fatalf("Scan: %v", err)
		}
		got = append(got, r)
	}
	corruptMemory := []byte("\xffPHOTO")
	want := []row{
		{name: []byte("Alice"), photo: corruptMemory},
		{name: []byte("Bob"), photo: corruptMemory},
		{name: []byte("Chris"), photo: corruptMemory},
	}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
	}

	var photo RawBytes
	err = db.QueryRow("SELECT|people|photo|name=?", "Alice").Scan(&photo)
	if err == nil {
		t.Error("want error scanning into RawBytes from QueryRow")
	}
}

func TestRowsColumns(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	rows, err := db.Query("SELECT|people|age,name|")
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	cols, err := rows.Columns()
	if err != nil {
		t.Fatalf("Columns: %v", err)
	}
	want := []string{"age", "name"}
	if !reflect.DeepEqual(cols, want) {
		t.Errorf("got %#v; want %#v", cols, want)
	}
	if err := rows.Close(); err != nil {
		t.Errorf("error closing rows: %s", err)
	}
}

func TestRowsColumnTypes(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	rows, err := db.Query("SELECT|people|age,name|")
	if err != nil {
		t.Fatalf("Query: %v", err)
	}
	tt, err := rows.ColumnTypes()
	if err != nil {
		t.Fatalf("ColumnTypes: %v", err)
	}

	types := make([]reflect.Type, len(tt))
	for i, tp := range tt {
		st := tp.ScanType()
		if st == nil {
			t.Errorf("scantype is null for column %q", tp.Name())
			continue
		}
		types[i] = st
	}
	values := make([]interface{}, len(tt))
	for i := range values {
		values[i] = reflect.New(types[i]).Interface()
	}
	ct := 0
	for rows.Next() {
		err = rows.Scan(values...)
		if err != nil {
			t.Fatalf("failed to scan values in %v", err)
		}
		ct++
		if ct == 0 {
			if values[0].(string) != "Bob" {
				t.Errorf("Expected Bob, got %v", values[0])
			}
			if values[1].(int) != 2 {
				t.Errorf("Expected 2, got %v", values[1])
			}
		}
	}
	if ct != 3 {
		t.Errorf("expected 3 rows, got %d", ct)
	}

	if err := rows.Close(); err != nil {
		t.Errorf("error closing rows: %s", err)
	}
}

func TestQueryRow(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	var name string
	var age int
	var birthday time.Time

	err := db.QueryRow("SELECT|people|age,name|age=?", 3).Scan(&age)
	if err == nil || !strings.Contains(err.Error(), "expected 2 destination arguments") {
		t.Errorf("expected error from wrong number of arguments; actually got: %v", err)
	}

	err = db.QueryRow("SELECT|people|bdate|age=?", 3).Scan(&birthday)
	if err != nil || !birthday.Equal(chrisBirthday) {
		t.Errorf("chris birthday = %v, err = %v; want %v", birthday, err, chrisBirthday)
	}

	err = db.QueryRow("SELECT|people|age,name|age=?", 2).Scan(&age, &name)
	if err != nil {
		t.Fatalf("age QueryRow+Scan: %v", err)
	}
	if name != "Bob" {
		t.Errorf("expected name Bob, got %q", name)
	}
	if age != 2 {
		t.Errorf("expected age 2, got %d", age)
	}

	err = db.QueryRow("SELECT|people|age,name|name=?", "Alice").Scan(&age, &name)
	if err != nil {
		t.Fatalf("name QueryRow+Scan: %v", err)
	}
	if name != "Alice" {
		t.Errorf("expected name Alice, got %q", name)
	}
	if age != 1 {
		t.Errorf("expected age 1, got %d", age)
	}

	var photo []byte
	err = db.QueryRow("SELECT|people|photo|name=?", "Alice").Scan(&photo)
	if err != nil {
		t.Fatalf("photo QueryRow+Scan: %v", err)
	}
	want := []byte("APHOTO")
	if !reflect.DeepEqual(photo, want) {
		t.Errorf("photo = %q; want %q", photo, want)
	}
}

func TestTxRollbackCommitErr(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)

	tx, err := db.Begin()
	if err != nil {
		t.Fatal(err)
	}
	err = tx.Rollback()
	if err != nil {
		t.Errorf("expected nil error from Rollback; got %v", err)
	}
	err = tx.Commit()
	if err != ErrTxDone {
		t.Errorf("expected %q from Commit; got %q", ErrTxDone, err)
	}

	tx, err = db.Begin()
	if err != nil {
		t.Fatal(err)
	}
	err = tx.Commit()
	if err != nil {
		t.Errorf("expected nil error from Commit; got %v", err)
	}
	err = tx.Rollback()
	if err != ErrTxDone {
		t.Errorf("expected %q from Rollback; got %q", ErrTxDone, err)
	}
}

func TestStatementErrorAfterClose(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	stmt, err := db.Prepare("SELECT|people|age|name=?")
	if err != nil {
		t.Fatalf("Prepare: %v", err)
	}
	err = stmt.Close()
	if err != nil {
		t.Fatalf("Close: %v", err)
	}
	var name string
	err = stmt.QueryRow("foo").Scan(&name)
	if err == nil {
		t.Errorf("expected error from QueryRow.Scan after Stmt.Close")
	}
}

func TestStatementQueryRow(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	stmt, err := db.Prepare("SELECT|people|age|name=?")
	if err != nil {
		t.Fatalf("Prepare: %v", err)
	}
	defer stmt.Close()
	var age int
	for n, tt := range []struct {
		name string
		want int
	}{
		{"Alice", 1},
		{"Bob", 2},
		{"Chris", 3},
	} {
		if err := stmt.QueryRow(tt.name).Scan(&age); err != nil {
			t.Errorf("%d: on %q, QueryRow/Scan: %v", n, tt.name, err)
		} else if age != tt.want {
			t.Errorf("%d: age=%d, want %d", n, age, tt.want)
		}
	}
}

type stubDriverStmt struct {
	err error
}

func (s stubDriverStmt) Close() error {
	return s.err
}

func (s stubDriverStmt) NumInput() int {
	return -1
}

func (s stubDriverStmt) Exec(args []driver.Value) (driver.Result, error) {
	return nil, nil
}

func (s stubDriverStmt) Query(args []driver.Value) (driver.Rows, error) {
	return nil, nil
}

// golang.org/issue/12798
func TestStatementClose(t *testing.T) {
	want := errors.New("STMT ERROR")

	tests := []struct {
		stmt *Stmt
		msg  string
	}{
		{&Stmt{stickyErr: want}, "stickyErr not propagated"},
		{&Stmt{tx: &Tx{}, txds: &driverStmt{Locker: &sync.Mutex{}, si: stubDriverStmt{want}}}, "driverStmt.Close() error not propagated"},
	}
	for _, test := range tests {
		if err := test.stmt.Close(); err != want {
			t.Errorf("%s. Got stmt.Close() = %v, want = %v", test.msg, err, want)
		}
	}
}

// golang.org/issue/3734
func TestStatementQueryRowConcurrent(t *testing.T) {
	db := newTestDB(t, "people")
	defer closeDB(t, db)
	stmt, err := db.Prepare("SELECT|people|age|name=?")
	if err != nil {
		t.Fatalf("Prepare: %v", err)
	}
	defer stmt.Close()

	const n = 10
	ch := make(chan error, n)
	for i := 0; i < n; i++ {
		go func() {
			var age int
			err := stmt.QueryRow("Alice").Scan(&age)
			if err == nil && age != 1 {
				err = fmt.Errorf("unexpected age %d", age)
			}
			ch <- err
		}()
	}
	for i := 0; i < n; i++ {
		if err := <-ch; err != nil {
			t.Error(err)
		}
	}
}

// just a test of fakedb itself
func TestBogusPreboundParameters(t *testing.T) {
	db := newTestDB(t, "foo")
	defer closeDB(t, db)
	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
	_, err := db.Prepare("INSERT|t1|name=?,age=bogusconversion")
	if err == nil {
		t.Fatalf("expected error")
	}
	if err.Error() != `fakedb: invalid conversion to int32 from "bogusconversion"` {
		t.Errorf("unexpected error: %v", err)
	}
}

func TestExec(t *testing.T) {
	db := newTestDB(t, "foo")
	defer closeDB(t, db)
	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
	stmt, err := db.Prepare("INSERT|t1|name=?,age=?")
	if err != nil {
		t.Errorf("Stmt, err = %v, %v", stmt, err)
	}
	defer stmt.Close()

	type execTest struct {
		args    []interface{}
		wantErr string
	}
	execTests := []execTest{
		// Okay:
		{[]interface{}{"Brad", 31}, ""},
		{[]interface{}{"Brad", int64(31)}, ""},
		{[]interface{}{"Bob", "32"}, ""},
		{[]interface{}{7, 9}, ""},

		// Invalid conversions:
		{[]interface{}{"Brad", int64(0xFFFFFFFF)}, "sql: converting argument $2 type: sql/driver: value 4294967295 overflows int32"},
		{[]interface{}{"Brad", "strconv fail"}, `sql: converting argument $2 type: sql/driver: value "strconv fail" can't be converted to int32`},

		// Wrong number of args:
		{[]interface{}{}, "sql: expected 2 arguments, got 0"},
		{[]interface{}{1, 2, 3}, "sql: expected 2 arguments, got 3"},
	}
	for n, et := range execTests {
		_, err := stmt.Exec(et.args...)
		errStr := ""
		if err != nil {
			errStr = err.Error()
		}
		if errStr != et.wantErr {
			t.Errorf("stmt.Execute #%d: for %v, got error %q, want error %q",
				n, et.args, errStr, et.wantErr)
		}
	}
}

func TestTxPrepare(t *testing.T) {
	db := newTestDB(t, "")
	defer closeDB(t, db)
	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
	tx, err := db.Begin()
	if err != nil {
		t.Fatalf("Begin = %v", err)
	}
	stmt, err := tx.Prepare("INSERT|t1|name=?,age=?")
	if err != nil {
		t.Fatalf("Stmt, err = %v, %v", stmt, err)
	}
	defer stmt.Close()
	_, err = stmt.Exec("Bobby", 7)
	if err != nil {
		t.Fatalf("Exec = %v", err)
	}
	err = tx.Commit()
	if err != nil {
		t.Fatalf("Commit = %v", err)
	}
	// Commit() should have closed the statement
	if !stmt.closed {
		t.Fatal("Stmt not closed after Commit")
	}
}

func TestTxStmt(t *testing.T) {
	db := newTestDB(t, "")
	defer closeDB(t, db)