func TestContentMountMerge(t *testing.T) {
	t.Parallel()

	files := `
-- config.toml --
baseURL = 'https://example.org/'
languageCode = 'en-us'
title = 'Hugo Forum Topic #37225'
theme = 'mytheme'

disableKinds = ['sitemap','RSS','taxonomy','term']
defaultContentLanguage = 'en'
defaultContentLanguageInSubdir = true

[languages.en]
languageName = 'English'
weight = 1
[languages.de]
languageName = 'Deutsch'
weight = 2
[languages.nl]
languageName = 'Nederlands'
weight = 3

# EN content
[[module.mounts]]
source = 'content/en'
target = 'content'
lang = 'en'

# DE content
[[module.mounts]]
source = 'content/de'
target = 'content'
lang = 'de'

# This fills in the gaps in DE content with EN content
[[module.mounts]]
source = 'content/en'
target = 'content'
lang = 'de'

# NL content
[[module.mounts]]
source = 'content/nl'
target = 'content'
lang = 'nl'

# This should fill in the gaps in NL content with EN content
[[module.mounts]]
source = 'content/en'
target = 'content'
lang = 'nl'

-- content/de/_index.md --
---
title: "home (de)"
---
-- content/de/p1.md --
---
title: "p1 (de)"
---
-- content/en/_index.md --
---
title: "home (en)"
---
-- content/en/p1.md --
---
title: "p1 (en)"
---
-- content/en/p2.md --
---
title: "p2 (en)"
---
-- content/en/p3.md --
---
title: "p3 (en)"
---
-- content/nl/_index.md --
---
title: "home (nl)"
---
-- content/nl/p1.md --
---
title: "p1 (nl)"
---
-- content/nl/p3.md --
---
title: "p3 (nl)"
---
-- layouts/home.html --
{{ .Title }}: {{ site.Language.Lang }}: {{ range site.RegularPages }}{{ .Title }}|{{ end }}:END
-- themes/mytheme/config.toml --
[[module.mounts]]
source = 'content/nlt'
target = 'content'
lang = 'nl'
-- themes/mytheme/content/nlt/p3.md --
---
title: "p3 theme (nl)"
---
-- themes/mytheme/content/nlt/p4.md --
---
title: "p4 theme (nl)"
---
`

	b := NewIntegrationTestBuilder(
		IntegrationTestConfig{
			T:           t,
			TxtarString: files,
		},
	).Build()

	b.AssertFileContent("public/nl/index.html", `home (nl): nl: p1 (nl)|p2 (en)|p3 (nl)|p4 theme (nl)|:END`)
	b.AssertFileContent("public/de/index.html", `home (de): de: p1 (de)|p2 (en)|p3 (en)|:END`)
	b.AssertFileContent("public/en/index.html", `home (en): en: p1 (en)|p2 (en)|p3 (en)|:END`)

}