Fix COLLATE issue for BLOB

Author: Sergey Podgornyy

column.go

@@ -295,13 +295,13 @@ func (s String) buildRow() string {
 //		longtext	➡️ migrator.Text{Prefix: "long", Default: "write you text", Charset: "utf8mb4", Collate: "utf8mb4_general_ci"}
 //			↪️ longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT 'write you text'
 //		tinyblob	➡️ migrator.Text{Prefix: "tiny", Blob: true}
-//			↪️ tinyblob COLLATE utf8mb4_unicode_ci NOT NULL
+//			↪️ tinyblob NOT NULL
 //		blob		➡️ migrator.Text{Blob: true}
-//			↪️ blob COLLATE utf8mb4_unicode_ci NOT NULL
+//			↪️ blob NOT NULL
 //		mediumblob	➡️ migrator.Text{Prefix: "medium", Blob: true}
-//			↪️ mediumblob COLLATE utf8mb4_unicode_ci NOT NULL
+//			↪️ mediumblob  NOT NULL
 //		longblob	➡️ migrator.Text{Prefix: "long", Blob: true}
-//			↪️ longblob COLLATE utf8mb4_unicode_ci NOT NULL
+//			↪️ longblob NOT NULL
 type Text struct {
 	Default  string
 	Nullable bool
@@ -330,7 +330,7 @@ func (t Text) buildRow() string {
 
 	if t.Collate != "" {
 		sql += " COLLATE " + t.Collate
-	} else if t.Charset == "" {
+	} else if t.Charset == "" && !t.Blob {
 		// use default
 		sql += " COLLATE utf8mb4_unicode_ci"
 	}

column_test.go

@@ -308,12 +308,12 @@ func TestText(t *testing.T) {
 
 	t.Run("it builds blob", func(t *testing.T) {
 		c := Text{Blob: true}
-		assert.Equal(t, "blob COLLATE utf8mb4_unicode_ci NOT NULL", c.buildRow())
+		assert.Equal(t, "blob NOT NULL", c.buildRow())
 	})
 
 	t.Run("it builds blob with prefix", func(t *testing.T) {
 		c := Text{Prefix: "tiny", Blob: true}
-		assert.Equal(t, "tinyblob COLLATE utf8mb4_unicode_ci NOT NULL", c.buildRow())
+		assert.Equal(t, "tinyblob NOT NULL", c.buildRow())
 	})
 
 	t.Run("it builds with charset", func(t *testing.T) {
@@ -349,7 +349,7 @@ func TestText(t *testing.T) {
 	t.Run("it builds string with all parameters", func(t *testing.T) {
 		c := Text{
 			Prefix:   "long",
-			Blob:     true,
+			Blob:     false,
 			Nullable: true,
 			Charset:  "utf8mb4",
 			Collate:  "utf8mb4_general_ci",
@@ -360,7 +360,7 @@ func TestText(t *testing.T) {
 
 		assert.Equal(
 			t,
-			"longblob CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT 'nice' ON UPDATE set null COMMENT 'test'",
+			"longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT 'nice' ON UPDATE set null COMMENT 'test'",
 			c.buildRow(),
 		)
 	})