diff --git a/tsdb/tsm1/engine_test.go b/tsdb/tsm1/engine_test.go
index 2c35d94c17..5d2da0c45f 100644
--- a/tsdb/tsm1/engine_test.go
+++ b/tsdb/tsm1/engine_test.go
@@ -656,6 +656,10 @@ func TestEngine_DeleteSeriesRange_OutsideTime(t *testing.T) {
 }
 
 func TestEngine_LastModified(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
 	// Create a few points.
 	p1 := MustParsePointString("cpu,host=A value=1.1 1000000000")
 	p2 := MustParsePointString("cpu,host=B value=1.2 2000000000")
diff --git a/tsdb/tsm1/file_store_test.go b/tsdb/tsm1/file_store_test.go
index ef62b6e9c6..a17ef51cf5 100644
--- a/tsdb/tsm1/file_store_test.go
+++ b/tsdb/tsm1/file_store_test.go
@@ -2418,6 +2418,10 @@ func TestFileStore_Remove(t *testing.T) {
 }
 
 func TestFileStore_Replace(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
 	dir := MustTempDir()
 	defer os.RemoveAll(dir)
 
@@ -2505,7 +2509,6 @@ func TestFileStore_Replace(t *testing.T) {
 	if _, err := os.Stat(files[2]); err != nil {
 		t.Fatalf("stat file: %v", err)
 	}
-
 }
 
 func TestFileStore_Open_Deleted(t *testing.T) {
diff --git a/tsdb/tsm1/writer_test.go b/tsdb/tsm1/writer_test.go
index c355426970..b7bf78dc0d 100644
--- a/tsdb/tsm1/writer_test.go
+++ b/tsdb/tsm1/writer_test.go
@@ -556,12 +556,8 @@ func TestTSMWriter_WriteBlock_MaxKey(t *testing.T) {
 		t.Fatalf("unexpected error creating writer: %v", err)
 	}
 
-	var key string
-	for i := 0; i < 100000; i++ {
-		key += "a"
-	}
-
-	if err := w.WriteBlock([]byte(key), 0, 0, nil); err != tsm1.ErrMaxKeyLengthExceeded {
+	key := bytes.Repeat([]byte("a"), 100000)
+	if err := w.WriteBlock(key, 0, 0, nil); err != tsm1.ErrMaxKeyLengthExceeded {
 		t.Fatalf("expected max key length error writing key: %v", err)
 	}
 }
@@ -577,11 +573,8 @@ func TestTSMWriter_Write_MaxKey(t *testing.T) {
 		t.Fatalf("unexpected error created writer: %v", err)
 	}
 
-	var key string
-	for i := 0; i < 100000; i++ {
-		key += "a"
-	}
-	if err := w.Write([]byte(key), []tsm1.Value{tsm1.NewValue(0, 1.0)}); err != tsm1.ErrMaxKeyLengthExceeded {
+	key := bytes.Repeat([]byte("a"), 100000)
+	if err := w.Write(key, []tsm1.Value{tsm1.NewValue(0, 1.0)}); err != tsm1.ErrMaxKeyLengthExceeded {
 		t.Fatalf("expected max key length error writing key: %v", err)
 	}
 }