internal: update page check and server tests

Fixes pagecheck for the recently rolled out
sticky header and enables the sticky header
experiment in the server tests.

Change-Id: I140bc22ed2c37304883d177228b59bda5c65441f
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/304511
Trust: Jamal Carvalho <jamal@golang.org>
Run-TryBot: Jamal Carvalho <jamal@golang.org>
Reviewed-by: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
diff --git a/internal/frontend/server_test.go b/internal/frontend/server_test.go
index 3231e99..29bcae8 100644
--- a/internal/frontend/server_test.go
+++ b/internal/frontend/server_test.go
@@ -1148,10 +1148,11 @@
 		experiments   []string
 	}{
 		{
-			name: "no experiments",
+			name: "sticky header",
 			testCasesFunc: func() []serverTestCase {
 				return append(serverTestCases(), linksTestCases...)
 			},
+			experiments: []string{internal.ExperimentStickyHeader},
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
diff --git a/internal/testing/pagecheck/pagecheck.go b/internal/testing/pagecheck/pagecheck.go
index 829476c..a5a20a4 100644
--- a/internal/testing/pagecheck/pagecheck.go
+++ b/internal/testing/pagecheck/pagecheck.go
@@ -97,11 +97,11 @@
 		in(`[data-test-id="UnitHeader-imports"]`,
 			in("a",
 				href(urlPath+"?tab=imports"),
-				text(`[0-9]+\+? Imports`))),
+				text(`Imports: [0-9]+\+?`))),
 		in(`[data-test-id="UnitHeader-importedby"]`,
 			in("a",
 				href(urlPath+"?tab=importedby"),
-				text(`[0-9]+\+? Imported by`))))
+				text(`Imported by: [0-9]+\+?`))))
 	if !isPackage {
 		importsDetails = nil
 	}
@@ -120,7 +120,7 @@
 			),
 		)
 	}
-	return in("header.LegacyUnitHeader",
+	return in("",
 		versionBadge(p),
 		in(`[data-test-id="UnitHeader-breadcrumbCurrent"]`, text(curBreadcrumb)),
 		in(`[data-test-id="UnitHeader-title"]`, text(p.Title)),
@@ -128,7 +128,7 @@
 		in(`[data-test-id="UnitHeader-version"]`,
 			in("a",
 				href("?tab=versions"),
-				exactText("Version "+p.FormattedVersion))),
+				exactText("Version: "+p.FormattedVersion))),
 		in(`[data-test-id="UnitHeader-commitTime"]`,
 			text(p.CommitTime)),
 		in(`[data-test-id="UnitHeader-licenses"]`,