Fix migration step not checked against current version.

Add tests for DropColumns.

pkg/database/migrate/migrate.go

@@ -53,7 +53,6 @@ DELETE FROM migration where revision = ?
 // Implementation details is specific for each database,
 // see migrate/sqlite.go for implementation reference.
 type Operation interface {
-
 	CreateTable(tableName string, args []string) (sql.Result, error)
 
 	RenameTable(tableName, newName string) (sql.Result, error)
@@ -147,7 +146,7 @@ func (m *Migration) up(target, current int64) error {
 
 	// loop through and execute revisions
 	for _, rev := range m.revs {
-		if rev.Revision() >= target {
+		if rev.Revision() > current {
 			current = rev.Revision()
 			// execute the revision Upgrade.
 			if err := rev.Up(op); err != nil {
@@ -191,7 +190,7 @@ func (m *Migration) down(target, current int64) error {
 			current = rev.Revision()
 			// execute the revision Upgrade.
 			if err := rev.Down(op); err != nil {
-				log.Printf("Failed to downgrade to Revision Number %v\n", current)
+				log.Printf("Failed to downgrade from Revision Number %v\n", current)
 				log.Println(err)
 				return tx.Rollback()
 			}
@@ -202,7 +201,7 @@ func (m *Migration) down(target, current int64) error {
 				return tx.Rollback()
 			}
 
-			log.Printf("Successfully downgraded to Revision %v\n", current)
+			log.Printf("Successfully downgraded from Revision %v\n", current)
 		}
 	}
 

pkg/database/migrate/sqlite.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"strings"
 
-	_ "github.com/mattn/go-sqlite3"
 	"github.com/dchest/uniuri"
+	_ "github.com/mattn/go-sqlite3"
 )
 
 type SQLiteDriver MigrationDriver
@@ -48,7 +48,8 @@ func (s *SQLiteDriver) DropColumns(tableName string, columnsToDrop []string) (sq
 	}
 
 	columnNames := selectName(columns)
-	preparedColumns := make([]string, len(columnNames)-len(columnsToDrop))
+
+	var preparedColumns []string
 	for k, column := range columnNames {
 		listed := false
 		for _, dropped := range columnsToDrop {
@@ -98,8 +99,8 @@ func (s *SQLiteDriver) RenameColumns(tableName string, columnChanges map[string]
 		return nil, err
 	}
 
-	oldColumns := make([]string, len(columnChanges))
+	var oldColumns []string
-	newColumns := make([]string, len(columnChanges))
+	var newColumns []string
 	for k, column := range selectName(columns) {
 		for Old, New := range columnChanges {
 			if column == Old {
@@ -126,7 +127,7 @@ func (s *SQLiteDriver) RenameColumns(tableName string, columnChanges map[string]
 
 func (s *SQLiteDriver) getDDLFromTable(tableName string) (string, error) {
 	var sql string
-	query := `SELECT sql FROM sqlite_master WHERE type='table' and name='?';`
+	query := `SELECT sql FROM sqlite_master WHERE type='table' and name=?;`
 	err := s.Tx.QueryRow(query, tableName).Scan(&sql)
 	if err != nil {
 		return "", err

pkg/database/migrate/sqlite_test.go

@@ -76,6 +76,29 @@ func (r *revision2) Revision() int64 {
 
 // ---------- end of revision 2
 
+// ---------- revision 3
+
+type revision3 struct{}
+
+func (r *revision3) Up(op Operation) error {
+	if _, err := op.AddColumn("samples", "url VARCHAR(255)"); err != nil {
+		return err
+	}
+	_, err := op.AddColumn("samples", "likes INTEGER")
+	return err
+}
+
+func (r *revision3) Down(op Operation) error {
+	_, err := op.DropColumns("samples", []string{"likes", "url"})
+	return err
+}
+
+func (r *revision3) Revision() int64 {
+	return 3
+}
+
+// ---------- end of revision 3
+
 var db *sql.DB
 
 var testSchema = `
@@ -144,6 +167,51 @@ func TestMigrateRenameTable(t *testing.T) {
 	}
 }
 
+type TableInfo struct {
+	CID       int64       `meddler:"cid,pk"`
+	Name      string      `meddler:"name"`
+	Type      string      `meddler:"type"`
+	Notnull   bool        `meddler:"notnull"`
+	DfltValue interface{} `meddler:"dflt_value"`
+	PK        bool        `meddler:"pk"`
+}
+
+func TestMigrateAddRemoveColumns(t *testing.T) {
+	defer tearDown()
+	if err := setUp(); err != nil {
+		t.Fatalf("Error preparing database: %q", err)
+	}
+
+	Driver = SQLite
+
+	mgr := New(db)
+	if err := mgr.Add(&revision1{}).Add(&revision3{}).Migrate(); err != nil {
+		t.Errorf("Can not migrate: %q", err)
+	}
+
+	var columns []*TableInfo
+	if err := meddler.QueryAll(db, &columns, `PRAGMA table_info(samples);`); err != nil {
+		t.Errorf("Can not access table info: %q", err)
+	}
+
+	if len(columns) < 5 {
+		t.Errorf("Expect length columns: %d\nGot: %d", 5, len(columns))
+	}
+
+	if err := mgr.MigrateTo(1); err != nil {
+		t.Errorf("Can not migrate: %q", err)
+	}
+
+	var another_columns []*TableInfo
+	if err := meddler.QueryAll(db, &another_columns, `PRAGMA table_info(samples);`); err != nil {
+		t.Errorf("Can not access table info: %q", err)
+	}
+
+	if len(another_columns) != 3 {
+		t.Errorf("Expect length columns: %d\nGot: %d", 3, len(columns))
+	}
+}
+
 func setUp() error {
 	var err error
 	db, err = sql.Open("sqlite3", "migration_tests.sqlite")

pkg/database/migrate/util.go

@@ -15,7 +15,7 @@ func fetchColumns(sql string) ([]string, error) {
 }
 
 func selectName(columns []string) []string {
-	results := make([]string, len(columns))
+	var results []string
 	for _, column := range columns {
 		col := strings.SplitN(strings.Trim(column, " \n\t"), " ", 2)
 		results = append(results, col[0])
@@ -24,7 +24,7 @@ func selectName(columns []string) []string {
 }
 
 func setForUpdate(left []string, right []string) string {
-	results := make([]string, len(left))
+	var results []string
 	for k, str := range left {
 		results = append(results, fmt.Sprintf("%s = %s", str, right[k]))
 	}