diff --git a/head_test.go b/head_test.go
index 535a94fad..457cd1003 100644
--- a/head_test.go
+++ b/head_test.go
@@ -204,8 +204,8 @@ func TestHead_Truncate(t *testing.T) {
 		{minTime: 3000, maxTime: 3999},
 	}, h.series.getByID(s2.ref).chunks)
 
-	testutil.Nil(t, h.series.getByID(s3.ref), "")
-	testutil.Nil(t, h.series.getByID(s4.ref), "")
+	testutil.Assert(t, h.series.getByID(s3.ref) == nil, "")
+	testutil.Assert(t, h.series.getByID(s4.ref) == nil, "")
 
 	postingsA1, _ := expandPostings(h.postings.get("a", "1"))
 	postingsA2, _ := expandPostings(h.postings.get("a", "2"))
@@ -218,8 +218,8 @@ func TestHead_Truncate(t *testing.T) {
 	testutil.Equals(t, []uint64{s2.ref}, postingsA2)
 	testutil.Equals(t, []uint64{s1.ref, s2.ref}, postingsB1)
 	testutil.Equals(t, []uint64{s1.ref, s2.ref}, postingsAll)
-	testutil.Nil(t, postingsB2, "")
-	testutil.Nil(t, postingsC1, "")
+	testutil.Assert(t, postingsB2 == nil, "")
+	testutil.Assert(t, postingsC1 == nil, "")
 
 	testutil.Equals(t, map[string]struct{}{
 		"":  struct{}{}, // from 'all' postings list
@@ -252,13 +252,13 @@ func TestMemSeries_truncateChunks(t *testing.T) {
 	lastID := s.chunkID(countBefore - 1)
 	lastChunk := s.chunk(lastID)
 
-	testutil.NotNil(t, s.chunk(0), "")
-	testutil.NotNil(t, lastChunk, "")
+	testutil.Assert(t, s.chunk(0) != nil, "")
+	testutil.Assert(t, lastChunk != nil, "")
 
 	s.truncateChunksBefore(2000)
 
 	testutil.Equals(t, int64(2000), s.chunks[0].minTime)
-	testutil.Nil(t, s.chunk(0), "first chunks not gone")
+	testutil.Assert(t, s.chunk(0) == nil, "first chunks not gone")
 	testutil.Equals(t, countBefore/2, len(s.chunks))
 	testutil.Equals(t, lastChunk, s.chunk(lastID))
 
diff --git a/postings_test.go b/postings_test.go
index 38e0d2e0b..b75f3bcf4 100644
--- a/postings_test.go
+++ b/postings_test.go
@@ -324,7 +324,7 @@ func TestBigEndian(t *testing.T) {
 		}
 
 		testutil.Assert(t, bep.Next() == false, "")
-		testutil.Nil(t, bep.Err(), "")
+		testutil.Assert(t, bep.Err() == nil, "")
 	})
 
 	t.Run("Seek", func(t *testing.T) {
@@ -370,7 +370,7 @@ func TestBigEndian(t *testing.T) {
 		for _, v := range table {
 			testutil.Equals(t, v.found, bep.Seek(uint64(v.seek)))
 			testutil.Equals(t, uint64(v.val), bep.At())
-			testutil.Nil(t, bep.Err(), "")
+			testutil.Assert(t, bep.Err() == nil, "")
 		}
 	})
 }
diff --git a/testutil/testutil.go b/testutil/testutil.go
index ec78025e4..cde0e4f91 100644
--- a/testutil/testutil.go
+++ b/testutil/testutil.go
@@ -65,65 +65,3 @@ func Equals(tb testing.TB, exp, act interface{}) {
 		tb.FailNow()
 	}
 }
-
-// from stretchr/testify
-
-// Copyright (c) 2012 - 2013 Mat Ryer and Tyler Bunnell
-
-// Please consider promoting this project if you find it useful.
-
-// Permission is hereby granted, free of charge, to any person
-// obtaining a copy of this software and associated documentation
-// files (the "Software"), to deal in the Software without restriction,
-// including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software,
-// and to permit persons to whom the Software is furnished to do so,
-// subject to the following conditions:
-
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
-// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
-// OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
-// OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-// isNil checks if a specified object is nil or not, without Failing.
-func isNil(object interface{}) bool {
-	if object == nil {
-		return true
-	}
-
-	value := reflect.ValueOf(object)
-	kind := value.Kind()
-	if kind >= reflect.Chan && kind <= reflect.Slice && value.IsNil() {
-		return true
-	}
-
-	return false
-}
-
-// modified from stretchr/testify
-// Nil asserts that the specified object is nil.
-//
-//    assert.Nil(t, err)
-//
-// Returns whether the assertion was successful (true) or not (false).
-func Nil(tb testing.TB, object interface{}, msg string) {
-	if !isNil(object) {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d:\n\n\texp: %#v to be nil\n\n\tmsg: %#v\033[39m\n\n", filepath.Base(file), line, object, msg)
-		tb.FailNow()
-	}
-}
-
-func NotNil(tb testing.TB, object interface{}, msg string) {
-	if isNil(object) {
-		_, file, line, _ := runtime.Caller(1)
-		fmt.Printf("\033[31m%s:%d:\n\n\texp: %#v to not be nil\n\n\tmsg: %#v\033[39m\n\n", filepath.Base(file), line, object, msg)
-		tb.FailNow()
-	}
-}