dashboard/app: modernize tests

Use expectOK for checking errors more.
Use pollEmailBug helper more.
Add expectNE and use it.

7 files changed, 63 insertions, 138 deletions

diff --git a/dashboard/app/access_test.go b/dashboard/app/access_test.go
index c02ea1d63..c331fa242 100644
--- a/dashboard/app/access_test.go
+++ b/dashboard/app/access_test.go
@@ -73,13 +73,9 @@ func TestAccess(t *testing.T) {
 	// noteBugAccessLevel collects all entities associated with the extID bug.
 	noteBugAccessLevel := func(extID string, level AccessLevel) {
 		bug, _, err := findBugByReportingID(c.ctx, extID)
-		if err != nil {
-			t.Fatal(err)
-		}
+		c.expectOK(err)
 		crash, _, err := findCrashForBug(c.ctx, bug)
-		if err != nil {
-			t.Fatal(err)
-		}
+		c.expectOK(err)
 		bugID := bug.keyHash()
 		entities = append(entities, []entity{
 			{
@@ -147,9 +143,7 @@ func TestAccess(t *testing.T) {
 	// noteBuildccessLevel collects all entities associated with the kernel build buildID.
 	noteBuildccessLevel := func(ns, buildID string) {
 		build, err := loadBuild(c.ctx, ns, buildID)
-		if err != nil {
-			t.Fatal(err)
-		}
+		c.expectOK(err)
 		entities = append(entities, entity{
 			level: config.Namespaces[ns].AccessLevel,
 			ref:   build.ID,
diff --git a/dashboard/app/app_test.go b/dashboard/app/app_test.go
index 3987b024d..851410722 100644
--- a/dashboard/app/app_test.go
+++ b/dashboard/app/app_test.go
@@ -368,9 +368,7 @@ func TestPurgeOldCrashes(t *testing.T) {
 	}
 	bug, _, _ := c.loadBug(rep.ID)
 	crashes, _, err := queryCrashesForBug(c.ctx, bug.key(c.ctx), 10*totalReported)
-	if err != nil {
-		c.t.Fatal(err)
-	}
+	c.expectOK(err)
 	// First, count how many crashes of different types we have.
 	// We should get all 3 reported crashes + some with repros and some without repros.
 	reported, norepro, repro := 0, 0, 0
@@ -396,9 +394,7 @@ func TestPurgeOldCrashes(t *testing.T) {
 			continue
 		}
 		idx, err := strconv.Atoi(string(crash.ReproOpts))
-		if err != nil {
-			c.t.Fatal(err)
-		}
+		c.expectOK(err)
 		count := norepro
 		if crash.ReproSyz != 0 {
 			count = repro
diff --git a/dashboard/app/email_test.go b/dashboard/app/email_test.go
index 1fd6a81e8..012e50f12 100644
--- a/dashboard/app/email_test.go
+++ b/dashboard/app/email_test.go
@@ -28,15 +28,11 @@ func TestEmailReport(t *testing.T) {
 	// Report the crash over email and check all fields.
 	var sender0, extBugID0, body0 string
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		sender0 = msg.Sender
 		body0 = msg.Body
 		sender, extBugID, err := email.RemoveAddrContext(msg.Sender)
-		if err != nil {
-			t.Fatalf("failed to remove sender context: %v", err)
-		}
+		c.expectOK(err)
 		extBugID0 = extBugID
 		_, dbCrash, dbBuild := c.loadBug(extBugID0)
 		crashLogLink := externalLink(c.ctx, textCrashLog, dbCrash.Log)
@@ -129,14 +125,10 @@ For more options, visit https://groups.google.com/d/optout.
 	c.client2.ReportCrash(crash)
 
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(msg.Sender, sender0)
 		sender, _, err := email.RemoveAddrContext(msg.Sender)
-		if err != nil {
-			t.Fatalf("failed to remove sender context: %v", err)
-		}
+		c.expectOK(err)
 		_, dbCrash, dbBuild := c.loadBug(extBugID0)
 		reproSyzLink := externalLink(c.ctx, textReproSyz, dbCrash.ReproSyz)
 		crashLogLink := externalLink(c.ctx, textCrashLog, dbCrash.Log)
@@ -181,17 +173,11 @@ report1
 
 	sender1, extBugID1 := "", ""
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		sender1 = msg.Sender
-		if sender1 == sender0 {
-			t.Fatalf("same ID in different reporting")
-		}
+		c.expectNE(sender1, sender0)
 		sender, extBugID, err := email.RemoveAddrContext(msg.Sender)
-		if err != nil {
-			t.Fatalf("failed to remove sender context: %v", err)
-		}
+		c.expectOK(err)
 		extBugID1 = extBugID
 		_, dbCrash, dbBuild := c.loadBug(extBugID1)
 		reproSyzLink := externalLink(c.ctx, textReproSyz, dbCrash.ReproSyz)
@@ -260,14 +246,10 @@ Content-Type: text/plain
 	c.client2.ReportCrash(crash)
 
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(msg.Sender, sender1)
 		sender, _, err := email.RemoveAddrContext(msg.Sender)
-		if err != nil {
-			t.Fatalf("failed to remove sender context: %v", err)
-		}
+		c.expectOK(err)
 		_, dbCrash, dbBuild := c.loadBug(extBugID1)
 		reproCLink := externalLink(c.ctx, textReproC, dbCrash.ReproC)
 		reproSyzLink := externalLink(c.ctx, textReproSyz, dbCrash.ReproSyz)
@@ -321,9 +303,7 @@ Content-Type: text/plain
 	c.expectOK(c.POST("/_ah/mail/", incoming4))
 
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(msg.To, []string{"<foo@bar.com>"})
 		c.expectEQ(msg.Subject, "Re: title1")
 		c.expectEQ(msg.Headers["In-Reply-To"], []string{"<abcdef>"})
@@ -358,13 +338,9 @@ unknown command "bad-command"
 	// New crash must produce new bug in the first reporting.
 	c.client2.ReportCrash(crash)
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(msg.Subject, crash.Title+" (2)")
-		if msg.Sender == sender0 {
-			t.Fatalf("same reporting ID for new bug")
-		}
+		c.expectNE(msg.Sender, sender0)
 	}
 }
 
@@ -379,9 +355,7 @@ func TestEmailNoMaintainers(t *testing.T) {
 	crash := testCrash(build, 1)
 	c.client2.ReportCrash(crash)
 
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
-	sender := (<-c.emailSink).Sender
+	sender := c.pollEmailBug().Sender
 
 	incoming1 := fmt.Sprintf(`Sender: syzkaller@googlegroups.com
 Date: Tue, 15 Aug 2017 14:59:00 -0700
@@ -437,9 +411,7 @@ func TestEmailDup(t *testing.T) {
 	// New crash must produce new bug in the first reporting.
 	c.client2.ReportCrash(crash2)
 	{
-		c.expectOK(c.GET("/email_poll"))
-		c.expectEQ(len(c.emailSink), 1)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(msg.Subject, crash2.Title+" (2)")
 	}
 }
diff --git a/dashboard/app/jobs_test.go b/dashboard/app/jobs_test.go
index 66d7b399f..70dc8acb3 100644
--- a/dashboard/app/jobs_test.go
+++ b/dashboard/app/jobs_test.go
@@ -33,25 +33,19 @@ func TestJob(t *testing.T) {
 	crash.Maintainers = []string{"maintainer@kernel.org"}
 	c.client2.ReportCrash(crash)
 
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
-	sender := (<-c.emailSink).Sender
+	sender := c.pollEmailBug().Sender
 	c.incomingEmail(sender, "#syz upstream\n")
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
-	sender = (<-c.emailSink).Sender
+	sender = c.pollEmailBug().Sender
 	_, extBugID, err := email.RemoveAddrContext(sender)
-	if err != nil {
-		t.Fatal(err)
-	}
+	c.expectOK(err)
 	mailingList := config.Namespaces["test2"].Reporting[1].Config.(*EmailConfig).Email
 	c.incomingEmail(sender, "bla-bla-bla", EmailOptFrom("maintainer@kernel.org"),
 		EmailOptCC([]string{mailingList, "kernel@mailing.list"}))
 
 	c.incomingEmail(sender, "#syz test: git://git.git/git.git kernel-branch\n"+patch,
 		EmailOptFrom("test@requester.com"), EmailOptCC([]string{mailingList}))
-	c.expectEQ(len(c.emailSink), 1)
-	c.expectEQ(strings.Contains((<-c.emailSink).Body, "This crash does not have a reproducer"), true)
+	body := c.pollEmailBug().Body
+	c.expectEQ(strings.Contains(body, "This crash does not have a reproducer"), true)
 
 	// Report crash with repro.
 	crash.ReproOpts = []byte("repro opts")
@@ -59,24 +53,23 @@ func TestJob(t *testing.T) {
 	crash.ReproC = []byte("repro C")
 	c.client2.ReportCrash(crash)
 
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
-	c.expectEQ(strings.Contains((<-c.emailSink).Body, "syzbot has found a reproducer"), true)
+	body = c.pollEmailBug().Body
+	c.expectEQ(strings.Contains(body, "syzbot has found a reproducer"), true)
 
 	c.incomingEmail(sender, "#syz test: repo",
 		EmailOptFrom("test@requester.com"), EmailOptCC([]string{mailingList}))
-	c.expectEQ(len(c.emailSink), 1)
-	c.expectEQ(strings.Contains((<-c.emailSink).Body, "want 2 args"), true)
+	body = c.pollEmailBug().Body
+	c.expectEQ(strings.Contains(body, "want 2 args"), true)
 
 	c.incomingEmail(sender, "#syz test: repo branch commit",
 		EmailOptFrom("test@requester.com"), EmailOptCC([]string{mailingList}))
-	c.expectEQ(len(c.emailSink), 1)
-	c.expectEQ(strings.Contains((<-c.emailSink).Body, "want 2 args"), true)
+	body = c.pollEmailBug().Body
+	c.expectEQ(strings.Contains(body, "want 2 args"), true)
 
 	c.incomingEmail(sender, "#syz test: repo branch",
 		EmailOptFrom("test@requester.com"), EmailOptCC([]string{mailingList}))
-	c.expectEQ(len(c.emailSink), 1)
-	c.expectEQ(strings.Contains((<-c.emailSink).Body, "does not look like a valid git repo"), true)
+	body = c.pollEmailBug().Body
+	c.expectEQ(strings.Contains(body, "does not look like a valid git repo"), true)
 
 	c.incomingEmail(sender, "#syz test: git://git.git/git.git kernel-branch\n"+patch,
 		EmailOptFrom("\"foo\" <blAcklisteD@dOmain.COM>"))
@@ -102,7 +95,7 @@ func TestJob(t *testing.T) {
 	pollResp, _ = c.client2.JobPoll([]string{"foobar"})
 	c.expectEQ(pollResp.ID, "")
 	pollResp, _ = c.client2.JobPoll([]string{build.Manager})
-	c.expectEQ(pollResp.ID != "", true)
+	c.expectNE(pollResp.ID, "")
 	c.expectEQ(pollResp.Manager, build.Manager)
 	c.expectEQ(pollResp.KernelRepo, "git://git.git/git.git")
 	c.expectEQ(pollResp.KernelBranch, "kernel-branch")
@@ -125,14 +118,12 @@ func TestJob(t *testing.T) {
 	}
 	c.client2.JobDone(jobDoneReq)
 
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
 	{
 		dbJob, dbBuild := c.loadJob(pollResp.ID)
 		patchLink := externalLink(c.ctx, textPatch, dbJob.Patch)
 		kernelConfigLink := externalLink(c.ctx, textKernelConfig, dbBuild.KernelConfig)
 		logLink := externalLink(c.ctx, textCrashLog, dbJob.CrashLog)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		to := email.MergeEmailLists([]string{"test@requester.com", "somebody@else.com", mailingList})
 		c.expectEQ(msg.To, to)
 		c.expectEQ(msg.Subject, "Re: "+crash.Title)
@@ -171,13 +162,11 @@ patch:          %[1]v
 		Error: []byte("failed to apply patch"),
 	}
 	c.client2.JobDone(jobDoneReq)
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
 	{
 		dbJob, dbBuild := c.loadJob(pollResp.ID)
 		patchLink := externalLink(c.ctx, textPatch, dbJob.Patch)
 		kernelConfigLink := externalLink(c.ctx, textKernelConfig, dbBuild.KernelConfig)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(len(msg.Attachments), 0)
 		body := fmt.Sprintf(`Hello,
 
@@ -211,14 +200,12 @@ patch:          %[1]v
 		Error: bytes.Repeat([]byte{'a', 'b', 'c'}, (maxInlineError+100)/3),
 	}
 	c.client2.JobDone(jobDoneReq)
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
 	{
 		dbJob, dbBuild := c.loadJob(pollResp.ID)
 		patchLink := externalLink(c.ctx, textPatch, dbJob.Patch)
 		errorLink := externalLink(c.ctx, textError, dbJob.Error)
 		kernelConfigLink := externalLink(c.ctx, textKernelConfig, dbBuild.KernelConfig)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(len(msg.Attachments), 0)
 		truncatedError := string(jobDoneReq.Error[len(jobDoneReq.Error)-maxInlineError:])
 		body := fmt.Sprintf(`Hello,
@@ -255,13 +242,11 @@ patch:          %[3]v
 		Build: *build,
 	}
 	c.client2.JobDone(jobDoneReq)
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
 	{
 		dbJob, dbBuild := c.loadJob(pollResp.ID)
 		patchLink := externalLink(c.ctx, textPatch, dbJob.Patch)
 		kernelConfigLink := externalLink(c.ctx, textKernelConfig, dbBuild.KernelConfig)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(len(msg.Attachments), 0)
 		body := fmt.Sprintf(`Hello,
 
@@ -302,14 +287,9 @@ func TestJobWithoutPatch(t *testing.T) {
 	crash.ReproOpts = []byte("repro opts")
 	crash.ReproSyz = []byte("repro syz")
 	c.client2.ReportCrash(crash)
-
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
-	sender := (<-c.emailSink).Sender
+	sender := c.pollEmailBug().Sender
 	_, extBugID, err := email.RemoveAddrContext(sender)
-	if err != nil {
-		t.Fatal(err)
-	}
+	c.expectOK(err)
 
 	c.incomingEmail(sender, "#syz test: git://mygit.com/git.git 5e6a2eea\n", EmailOptMessageID(1))
 	pollResp, _ := c.client2.JobPoll([]string{build.Manager})
@@ -322,12 +302,10 @@ func TestJobWithoutPatch(t *testing.T) {
 		Build: *testBuild,
 	}
 	c.client2.JobDone(jobDoneReq)
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
 	{
 		_, dbBuild := c.loadJob(pollResp.ID)
 		kernelConfigLink := externalLink(c.ctx, textKernelConfig, dbBuild.KernelConfig)
-		msg := <-c.emailSink
+		msg := c.pollEmailBug()
 		c.expectEQ(len(msg.Attachments), 0)
 		body := fmt.Sprintf(`Hello,
 
@@ -366,10 +344,7 @@ func TestJobRestrictedManager(t *testing.T) {
 	crash := testCrash(build, 1)
 	crash.ReproSyz = []byte("repro syz")
 	c.client2.ReportCrash(crash)
-
-	c.expectOK(c.GET("/email_poll"))
-	c.expectEQ(len(c.emailSink), 1)
-	sender := (<-c.emailSink).Sender
+	sender := c.pollEmailBug().Sender
 
 	// Testing on a wrong repo must fail and no test jobs passed to manager.
 	c.incomingEmail(sender, "#syz test: git://mygit.com/git.git master\n", EmailOptMessageID(1))
@@ -380,7 +355,7 @@ func TestJobRestrictedManager(t *testing.T) {
 	// Testing on the right repo must succeed.
 	c.incomingEmail(sender, "#syz test: git://restricted.git/restricted.git master\n", EmailOptMessageID(2))
 	pollResp, _ = c.client2.JobPoll([]string{build.Manager})
-	c.expectEQ(pollResp.ID != "", true)
+	c.expectNE(pollResp.ID, "")
 	c.expectEQ(pollResp.Manager, build.Manager)
 	c.expectEQ(pollResp.KernelRepo, "git://restricted.git/restricted.git")
 }
diff --git a/dashboard/app/notifications_test.go b/dashboard/app/notifications_test.go
index e6a7b6ba6..2223a2c33 100644
--- a/dashboard/app/notifications_test.go
+++ b/dashboard/app/notifications_test.go
@@ -36,9 +36,7 @@ func TestEmailNotifUpstreamEmbargo(t *testing.T) {
 	upstreamReport := c.pollEmailBug()
 	c.expectEQ(notifUpstream.Sender, report.Sender)
 	c.expectEQ(notifUpstream.Body, "Sending this report upstream.")
-	if upstreamReport.Sender == report.Sender {
-		t.Fatalf("upstream report from the same sender")
-	}
+	c.expectNE(upstreamReport.Sender, report.Sender)
 	c.expectEQ(upstreamReport.To, []string{"bugs@syzkaller.com", "default@maintainers.com"})
 }
 
@@ -67,9 +65,7 @@ func TestEmailNotifUpstreamSkip(t *testing.T) {
 	upstreamReport := c.pollEmailBug()
 	c.expectEQ(notifUpstream.Sender, report.Sender)
 	c.expectEQ(notifUpstream.Body, "Sending this report upstream.")
-	if upstreamReport.Sender == report.Sender {
-		t.Fatalf("upstream report from the same sender")
-	}
+	c.expectNE(upstreamReport.Sender, report.Sender)
 	c.expectEQ(upstreamReport.To, []string{"bugs@syzkaller.com", "default@maintainers.com"})
 }
 
diff --git a/dashboard/app/reporting_test.go b/dashboard/app/reporting_test.go
index 655bca8a3..74899b400 100644
--- a/dashboard/app/reporting_test.go
+++ b/dashboard/app/reporting_test.go
@@ -9,7 +9,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/google/go-cmp/cmp"
 	"github.com/google/syzkaller/dashboard/dashapi"
 )
 
@@ -37,9 +36,7 @@ func TestReportBug(t *testing.T) {
 	resp, _ = c.client.ReportingPollBugs("test")
 	c.expectEQ(len(resp.Reports), 1)
 	rep := resp.Reports[0]
-	if rep.ID == "" {
-		t.Fatalf("empty report ID")
-	}
+	c.expectNE(rep.ID, "")
 	_, dbCrash, dbBuild := c.loadBug(rep.ID)
 	want := &dashapi.BugReport{
 		Namespace:         "test1",
@@ -66,9 +63,7 @@ func TestReportBug(t *testing.T) {
 		NumCrashes:        1,
 		HappenedOn:        []string{"repo1 branch1"},
 	}
-	if diff := cmp.Diff(want, rep); diff != "" {
-		t.Fatal(diff)
-	}
+	c.expectEQ(want, rep)
 
 	// Since we did not update bug status yet, should get the same report again.
 	c.expectEQ(c.client.pollBug(), want)
@@ -80,18 +75,14 @@ func TestReportBug(t *testing.T) {
 	want.ReproSyz = []byte(syzReproPrefix + "#some opts\ngetpid()")
 	c.client.ReportCrash(crash1)
 	rep1 := c.client.pollBug()
-	if want.CrashID == rep1.CrashID {
-		t.Fatal("get the same CrashID for new crash")
-	}
+	c.expectNE(want.CrashID, rep1.CrashID)
 	_, dbCrash, _ = c.loadBug(rep.ID)
 	want.CrashID = rep1.CrashID
 	want.NumCrashes = 2
 	want.ReproSyzLink = externalLink(c.ctx, textReproSyz, dbCrash.ReproSyz)
 	want.LogLink = externalLink(c.ctx, textCrashLog, dbCrash.Log)
 	want.ReportLink = externalLink(c.ctx, textCrashReport, dbCrash.Report)
-	if diff := cmp.Diff(want, rep1); diff != "" {
-		t.Fatal(diff)
-	}
+	c.expectEQ(want, rep1)
 
 	reply, _ := c.client.ReportingUpdate(&dashapi.BugUpdate{
 		ID:         rep.ID,
@@ -118,17 +109,14 @@ func TestReportBug(t *testing.T) {
 
 	// Check that we get the report in the second reporting.
 	rep2 := c.client.pollBug()
-	if rep2.ID == "" || rep2.ID == rep.ID {
-		t.Fatalf("bad report ID: %q", rep2.ID)
-	}
+	c.expectNE(rep2.ID, "")
+	c.expectNE(rep2.ID, rep.ID)
 	want.ID = rep2.ID
 	want.First = true
 	want.Moderation = false
 	want.Config = []byte(`{"Index":2}`)
 	want.NumCrashes = 3
-	if diff := cmp.Diff(want, rep2); diff != "" {
-		t.Fatal(diff)
-	}
+	c.expectEQ(want, rep2)
 
 	// Check that that we can't upstream the bug in the final reporting.
 	reply, _ = c.client.ReportingUpdate(&dashapi.BugUpdate{
@@ -187,9 +175,7 @@ func TestInvalidBug(t *testing.T) {
 
 	// Now it should be reported again.
 	rep = c.client.pollBug()
-	if rep.ID == "" {
-		t.Fatalf("empty report ID")
-	}
+	c.expectNE(rep.ID, "")
 	_, dbCrash, dbBuild := c.loadBug(rep.ID)
 	want := &dashapi.BugReport{
 		Namespace:         "test1",
@@ -217,9 +203,7 @@ func TestInvalidBug(t *testing.T) {
 		NumCrashes:        1,
 		HappenedOn:        []string{"repo1 branch1"},
 	}
-	if diff := cmp.Diff(want, rep); diff != "" {
-		t.Fatal(diff)
-	}
+	c.expectEQ(want, rep)
 	c.client.ReportFailedRepro(testCrashID(crash1))
 }
 
diff --git a/dashboard/app/util_test.go b/dashboard/app/util_test.go
index 14722c90f..2f9d959c3 100644
--- a/dashboard/app/util_test.go
+++ b/dashboard/app/util_test.go
@@ -24,6 +24,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/google/syzkaller/dashboard/dashapi"
 	"golang.org/x/net/context"
 	"google.golang.org/appengine"
@@ -96,8 +97,14 @@ func (c *Ctx) expectForbidden(err error) {
 }
 
 func (c *Ctx) expectEQ(got, want interface{}) {
-	if !reflect.DeepEqual(got, want) {
-		c.t.Fatalf("\n%v: got %#v, want %#v", caller(0), got, want)
+	if diff := cmp.Diff(got, want); diff != "" {
+		c.t.Fatalf("\n%v: %v", caller(0), diff)
+	}
+}
+
+func (c *Ctx) expectNE(got, want interface{}) {
+	if reflect.DeepEqual(got, want) {
+		c.t.Fatalf("\n%v: equal: %#v", caller(0), got)
 	}
 }
 
@@ -124,6 +131,7 @@ func (c *Ctx) Close() {
 		for _, key := range keys {
 			c.expectOK(c.GET(fmt.Sprintf("/bug?id=%v", key.StringID())))
 		}
+		// No pending emails (tests need to consume them).
 		c.expectOK(c.GET("/email_poll"))
 		for len(c.emailSink) != 0 {
 			c.t.Errorf("ERROR: leftover email: %v", (<-c.emailSink).Body)