gpg: make tests more robust

Skip the tests if gpg is not installed.
Avoid interference with the global ~/.gnupg.
Automatically delete GNUPGHOME at the end of tests.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-by: Tim Culverhouse <tim@timculverhouse.com>

Makefile

@@ -58,6 +58,10 @@ checkfmt:
 		exit 1; \
 	fi
 
+.PHONY: tests
+tests:
+	$(GO) test $(GOFLAGS) -v ./...
+
 .PHONY: debug
 debug: aerc.debug
 	@echo 'Run `./aerc.debug` and use this command in another terminal to attach a debugger:'

lib/crypto/gpg/gpg_test.go

@@ -2,9 +2,8 @@ package gpg
 
 import (
 	"bytes"
-	"fmt"
 	"io"
-	"log"
+	"os"
 	"os/exec"
 	"strings"
 	"testing"
@@ -12,22 +11,20 @@ import (
 	"git.sr.ht/~rjarry/aerc/models"
 )
 
-func TestHasGpg(t *testing.T) {
-	gpgmail := new(Mail)
-	hasGpg := gpgmail.Init(new(log.Logger))
-
-	if hasGpg != nil {
-		t.Errorf("System does not have GPG")
+func initGPGtest(t *testing.T) {
+	if _, err := exec.LookPath("gpg"); err != nil {
+		t.Skipf("%s", err)
 	}
+	// temp dir is automatically deleted by the test runtime
+	dir := t.TempDir()
+	// t.Setenv is only available since go 1.17
+	if err := os.Setenv("GNUPGHOME", dir); err != nil {
+		t.Fatalf("failed to set GNUPGHOME: %s", err)
 	}
-
-func CleanUp() {
-	cmd := exec.Command("gpg", "--batch", "--yes", "--delete-secret-and-public-keys", testKeyId)
-	err := cmd.Run()
-	if err != nil {
-		fmt.Println("Test cleanup failed: you may need to delete the test keys from your GPG keyring")
-		return
-	}
+	t.Cleanup(func() {
+		os.Unsetenv("GNUPGHOME")
+	})
+	t.Logf("using GNUPGHOME = %s", dir)
 }
 
 func toCRLF(s string) string {

lib/crypto/gpg/reader_test.go

@@ -21,6 +21,8 @@ func importPublicKey() {
 }
 
 func TestReader_encryptedSignedPGPMIME(t *testing.T) {
+	initGPGtest(t)
+
 	var expect = models.MessageDetails{
 		IsEncrypted:        true,
 		IsSigned:           true,
@@ -41,11 +43,11 @@ func TestReader_encryptedSignedPGPMIME(t *testing.T) {
 	}
 
 	deepEqual(t, r.MessageDetails, &expect)
-
-	t.Cleanup(CleanUp)
 }
 
 func TestReader_signedPGPMIME(t *testing.T) {
+	initGPGtest(t)
+
 	var expect = models.MessageDetails{
 		IsEncrypted:        false,
 		IsSigned:           true,
@@ -67,11 +69,11 @@ func TestReader_signedPGPMIME(t *testing.T) {
 	}
 
 	deepEqual(t, r.MessageDetails, &expect)
-
-	t.Cleanup(CleanUp)
 }
 
 func TestReader_encryptedSignedEncapsulatedPGPMIME(t *testing.T) {
+	initGPGtest(t)
+
 	var expect = models.MessageDetails{
 		IsEncrypted:        true,
 		IsSigned:           true,
@@ -100,6 +102,8 @@ func TestReader_encryptedSignedEncapsulatedPGPMIME(t *testing.T) {
 	}
 }
 func TestReader_signedPGPMIMEInvalid(t *testing.T) {
+	initGPGtest(t)
+
 	var expect = models.MessageDetails{
 		IsEncrypted:        false,
 		IsSigned:           true,
@@ -120,11 +124,11 @@ func TestReader_signedPGPMIMEInvalid(t *testing.T) {
 		t.Fatalf("pgpmail.Read() = %v", err)
 	}
 	deepEqual(t, r.MessageDetails, &expect)
-
-	t.Cleanup(CleanUp)
 }
 
 func TestReader_plaintext(t *testing.T) {
+	initGPGtest(t)
+
 	sr := strings.NewReader(testPlaintext)
 	r, err := Read(sr)
 	if err != nil {

lib/crypto/gpg/writer_test.go

@@ -16,6 +16,8 @@ func init() {
 }
 
 func TestEncrypt(t *testing.T) {
+	initGPGtest(t)
+
 	importPublicKey()
 	importSecretKey()
 	var h textproto.Header
@@ -55,11 +57,11 @@ func TestEncrypt(t *testing.T) {
 	if s := body.String(); s != wantEncrypted {
 		t.Errorf("Encrypt() = \n%v\n but want \n%v", s, wantEncrypted)
 	}
-
-	t.Cleanup(CleanUp)
 }
 
 func TestSign(t *testing.T) {
+	initGPGtest(t)
+
 	importPublicKey()
 	importSecretKey()
 	var h textproto.Header