Backpack: Describe packages in tests using Hpack format

Author: mpilgrem

tests/integration/tests/backpack-cross-package-multi-inst/files/.gitignore

@@ -0,0 +1,6 @@
+app.cabal
+consumer-a.cabal
+consumer-b.cabal
+impl-a.cabal
+impl-b.cabal
+sig-pkg.cabal

tests/integration/tests/backpack-cross-package-multi-inst/files/app/app.cabal

@@ -0,0 +1,14 @@
+spec-version: 0.36.0
+
+name: app
+
+dependencies:
+- base
+
+executables:
+  multi-inst-demo:
+    source-dirs: app
+    main: Main.hs
+    dependencies:
+    - consumer-a
+    - consumer-b

tests/integration/tests/backpack-cross-package-multi-inst/files/app/package.yaml

@@ -0,0 +1,14 @@
+spec-version: 0.36.0
+
+name: consumer-a
+
+dependencies:
+- base
+
+library:
+  source-dirs: src
+  dependencies:
+    - name: sig-pkg
+      mixin:
+      - requires (Str as Str)
+    - impl-a

tests/integration/tests/backpack-cross-package-multi-inst/files/consumer-a/consumer-a.cabal

@@ -0,0 +1,14 @@
+spec-version: 0.36.0
+
+name: consumer-b
+
+dependencies:
+- base
+
+library:
+  source-dirs: src
+  dependencies:
+  - name: sig-pkg
+    mixin:
+    - requires (Str as Str)
+  - impl-b

tests/integration/tests/backpack-cross-package-multi-inst/files/consumer-a/package.yaml

@@ -0,0 +1,9 @@
+spec-version: 0.36.0
+
+name: impl-a
+
+dependencies:
+- base
+
+library:
+  source-dirs: src