Add comment for why we test two files for bundle_uuid (#1949)

## Changes
Addresses feedback from this thread
#1947 (comment)

libs/template/helpers_test.go

@@ -43,11 +43,16 @@ func TestTemplateBundleUuidFunction(t *testing.T) {
 	err = r.walk()
 	assert.NoError(t, err)
 
+	// We test the content of two generated files to ensure that the same UUID
+	// is used across all files generated by the template. Each file content is
+	// generated by a separate (*template.Template).Execute call, so testing different
+	// files ensures that the UUID is stable across all template execution calls.
+	copy := strings.Clone(bundleUuid)
 	assert.Len(t, r.files, 2)
 	c1 := strings.Trim(string(r.files[0].(*inMemoryFile).content), "\n\r")
-	assert.Equal(t, strings.Repeat(bundleUuid, 3), c1)
+	assert.Equal(t, strings.Repeat(copy, 3), c1)
 	c2 := strings.Trim(string(r.files[1].(*inMemoryFile).content), "\n\r")
-	assert.Equal(t, strings.Repeat(bundleUuid, 5), c2)
+	assert.Equal(t, strings.Repeat(copy, 5), c2)
 }
 
 func TestTemplateRegexpCompileFunction(t *testing.T) {