diff --git a/cmd/age/age_test.go b/cmd/age/age_test.go
index 975af17b..a95cdbe4 100644
--- a/cmd/age/age_test.go
+++ b/cmd/age/age_test.go
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build ignore
-
 package main
 
 import (
diff --git a/go.mod b/go.mod
index ad5526b4..eaaefd53 100644
--- a/go.mod
+++ b/go.mod
@@ -8,3 +8,12 @@ require (
 	golang.org/x/sys v0.3.0
 	golang.org/x/term v0.3.0
 )
+
+// Test dependencies.
+require (
+	github.com/creack/pty v1.1.18 // indirect
+	github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e // indirect
+	github.com/rogpeppe/go-internal v1.8.1
+)
+
+replace github.com/rogpeppe/go-internal => github.com/FiloSottile/go-internal v1.8.2-0.20220728122003-0ced171a3e0e
diff --git a/go.sum b/go.sum
index e5a1adce..3f691a98 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,11 @@
 filippo.io/edwards25519 v1.0.0 h1:0wAIcmJUqRdI8IJ/3eGi5/HwXZWPujYXXlkrQogz0Ek=
 filippo.io/edwards25519 v1.0.0/go.mod h1:N1IkdkCkiLB6tki+MYJoSx2JTY9NUlxZE7eHn5EwJns=
+github.com/FiloSottile/go-internal v1.8.2-0.20220728122003-0ced171a3e0e h1:hLDldUUKSNgXte+2H8yZzPVStWa7697IJer9wwfW/dg=
+github.com/FiloSottile/go-internal v1.8.2-0.20220728122003-0ced171a3e0e/go.mod h1:dNbK7mWDMlmf5ttOAJJg+a4CyamnqDRrw+Uja1sBETc=
+github.com/creack/pty v1.1.18 h1:n56/Zwd5o6whRC5PMGretI4IdRLlmBXYNjScPaBgsbY=
+github.com/creack/pty v1.1.18/go.mod h1:MOBLtS5ELjhRRrroQr9kyvTxUAFNvYEK993ew/Vr4O4=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e h1:aoZm08cpOy4WuID//EZDgcC4zIxODThtZNPirFr42+A=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 golang.org/x/crypto v0.4.0 h1:UVQgzMY87xqpKNgb+kDsll2Igd33HszWHFLmpaRMq/8=
 golang.org/x/crypto v0.4.0/go.mod h1:3quD/ATkf6oY+rnes5c3ExXTbLc8mueNue5/DoinL80=
 golang.org/x/sys v0.3.0 h1:w8ZOecv6NaNa/zC8944JTU3vz4u6Lagfk4RPQxv92NQ=