Add test for #7270

Author: fgaz

cabal-testsuite/PackageTests/MultipleLibraries/T7270/cabal.out

@@ -0,0 +1,20 @@
+# Setup configure
+Warning: dep.cabal:11:30: visibility is experimental feature (issue #5660)
+Configuring dep-0.1.0.0...
+# Setup build
+Preprocessing library 'sublib' for dep-0.1.0.0..
+Building library 'sublib' for dep-0.1.0.0..
+Preprocessing library for dep-0.1.0.0..
+Building library for dep-0.1.0.0..
+# Setup copy
+Installing internal library sublib in <PATH>
+Installing library in <PATH>
+# Setup register
+Registering library 'sublib' for dep-0.1.0.0..
+Registering library for dep-0.1.0.0..
+# Setup configure
+Warning: p.cabal:9:28: colon specifier is experimental feature (issue #5660)
+Configuring p-0.1.0.0...
+# Setup build
+Preprocessing library for p-0.1.0.0..
+Building library for p-0.1.0.0..

cabal-testsuite/PackageTests/MultipleLibraries/T7270/cabal.test.hs

@@ -0,0 +1,5 @@
+import Test.Cabal.Prelude
+main = setupAndCabalTest $
+  withPackageDb $ do
+    withDirectory "dep" $ setup_install []
+    withDirectory "p" $ setup_build []

cabal-testsuite/PackageTests/MultipleLibraries/T7270/dep/Sublib.hs

@@ -0,0 +1,4 @@
+module Sublib where
+
+s :: String
+s = "Hello World"

cabal-testsuite/PackageTests/MultipleLibraries/T7270/dep/dep.cabal

@@ -0,0 +1,14 @@
+cabal-version:       3.0
+name:                dep
+version:             0.1.0.0
+build-type:          Simple
+
+-- needed because of https://github.com/haskell/cabal/issues/8095
+library
+  default-language:    Haskell2010
+
+library sublib
+  visibility:          public
+  exposed-modules:     Sublib
+  build-depends:       base >=4 && <5
+  default-language:    Haskell2010

cabal-testsuite/PackageTests/MultipleLibraries/T7270/p/Main.hs

@@ -0,0 +1,6 @@
+module Main where
+
+import Sublib (s)
+
+main :: IO ()
+main = putStrLn s

cabal-testsuite/PackageTests/MultipleLibraries/T7270/p/p.cabal

@@ -0,0 +1,10 @@
+cabal-version:       3.0
+name:                p
+version:             0.1.0.0
+build-type:          Simple
+
+library
+  exposed-modules:     Main
+  build-depends:       base >=4 && <5
+                     , dep:sublib
+  default-language:    Haskell2010