internal/testing/sample: make a fresh copy of Imports

Create a new slice of imports each time it's used.

This ensures that memory isn't shared between sample modules.  It
addresses a race condition we saw when running postgres tests
concurrently.

Change-Id: I0c1e0112ff7b944433565c7cacdd7226a32ad4eb
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/294149
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>

1 files changed, 7 insertions, 3 deletions

diff --git a/internal/testing/sample/sample.go b/internal/testing/sample/sample.go
index 0418be09..d4ffff0e 100644
--- a/internal/testing/sample/sample.go
+++ b/internal/testing/sample/sample.go
@@ -47,7 +47,6 @@ var (
 	Suffix         = "foo"
 	PackagePath    = path.Join(ModulePath, Suffix)
 	V1Path         = PackagePath
-	Imports        = []string{"path/to/bar", "fmt"}
 	ReadmeFilePath = "README.md"
 	ReadmeContents = "readme"
 	GOOS           = internal.All
@@ -203,12 +202,13 @@ func UnitForModuleRoot(m *internal.ModuleInfo) *internal.Unit {
 func UnitForPackage(path, modulePath, version, name string, isRedistributable bool) *internal.Unit {
 	// Copy Doc because some tests modify it.
 	doc := *Doc
+	imps := Imports()
 	return &internal.Unit{
 		UnitMeta:        *UnitMeta(path, modulePath, version, name, isRedistributable),
 		Documentation:   []*internal.Documentation{&doc},
 		LicenseContents: Licenses(),
-		Imports:         Imports,
-		NumImports:      len(Imports),
+		Imports:         imps,
+		NumImports:      len(imps),
 	}
 }
 
@@ -380,3 +380,7 @@ func Licenses() []*licenses.License {
 		{Metadata: LicenseMetadata()[0], Contents: []byte(`Lorem Ipsum`)},
 	}
 }
+
+func Imports() []string {
+	return []string{"fmt", "path/to/bar"}
+}