diff --git a/unix_test.go b/unix_test.go
new file mode 100644
index 0000000..267eab1
--- /dev/null
+++ b/unix_test.go
@@ -0,0 +1,116 @@
+// +build !windows
+
+package bbolt_test
+
+import (
+	"fmt"
+	"testing"
+
+	bolt "go.etcd.io/bbolt"
+	"golang.org/x/sys/unix"
+)
+
+func TestMlock_DbOpen(t *testing.T) {
+	// 32KB
+	skipOnMemlockLimitBelow(t, 32*1024)
+
+	db := MustOpenWithOption(&bolt.Options{Mlock: true})
+	defer db.MustClose()
+}
+
+// Test change between "empty" (16KB) and "non-empty" db
+func TestMlock_DbCanGrow_Small(t *testing.T) {
+	// 32KB
+	skipOnMemlockLimitBelow(t, 32*1024)
+
+	db := MustOpenWithOption(&bolt.Options{Mlock: true})
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucketIfNotExists([]byte("bucket"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		key := []byte("key")
+		value := []byte("value")
+		if err := b.Put(key, value); err != nil {
+			t.Fatal(err)
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+}
+
+// Test crossing of 16MB (AllocSize) of db size
+func TestMlock_DbCanGrow_Big(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
+	// 32MB
+	skipOnMemlockLimitBelow(t, 32*1024*1024)
+
+	chunksBefore := 64
+	chunksAfter := 64
+
+	db := MustOpenWithOption(&bolt.Options{Mlock: true})
+	defer db.MustClose()
+
+	for chunk := 0; chunk < chunksBefore; chunk++ {
+		insertChunk(t, db, chunk)
+	}
+	dbSize := fileSize(db.f)
+
+	for chunk := 0; chunk < chunksAfter; chunk++ {
+		insertChunk(t, db, chunksBefore+chunk)
+	}
+	newDbSize := fileSize(db.f)
+
+	if newDbSize <= dbSize {
+		t.Errorf("db didn't grow: %v <= %v", newDbSize, dbSize)
+	}
+}
+
+func insertChunk(t *testing.T, db *DB, chunkId int) {
+	chunkSize := 1024
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucketIfNotExists([]byte("bucket"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		for i := 0; i < chunkSize; i++ {
+			key := []byte(fmt.Sprintf("key-%d-%d", chunkId, i))
+			value := []byte("value")
+			if err := b.Put(key, value); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Main reason for this check is travis limiting mlockable memory to 64KB
+// https://github.com/travis-ci/travis-ci/issues/2462
+func skipOnMemlockLimitBelow(t *testing.T, memlockLimitRequest uint64) {
+	var info unix.Rlimit
+	if err := unix.Getrlimit(unix.RLIMIT_MEMLOCK, &info); err != nil {
+		t.Fatal(err)
+	}
+
+	if info.Cur < memlockLimitRequest {
+		t.Skip(fmt.Sprintf(
+			"skipping as RLIMIT_MEMLOCK is unsufficient: %v < %v",
+			info.Cur,
+			memlockLimitRequest,
+		))
+	}
+}