Add test cases that reproduce #7241.

- Move project sdist tests to cabal-testsuite
- Add --ignore-project test
- Duplicate tests but without cabal.project
- Add a cabal.project one folder up
- Add a package Z in the root
- Rerun --accept with more immediate parent project
- Add a readme for the tests
- Fix problems with uv package, update expected output
- Add U and V modules
- Explain what is wrong with cabal.dot-uv.test.hs
- Add a note on cabal.no-project.test.hs
- Explain what is wrong with cabal.sub-pq.test.hs
- Explain what is wrong with cabal.sub-rs.test.hs
- Explain what is wrong with cabal.dot-uv.test.hs
- Leave a note explaining cabal.no-project.test.hs
- Leave a note explaining cabal.project.test.hs
- Leave a note explaining cabal.sub-pq.test.hs
- Explain what is wrong with cabal.sub-rs.test.hs
- Patches for project respecting behaviour
- Explain root ignore-project and no-project tests
- Add *.v2.test.hs variants exercising v2-sdist
- Add v2 patches, test out not using <ROOT>

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.out

+# cabal sdist
+Wrote tarball sdist to <ROOT>/cabal.dot-uv.dist/work/./dist/sdist/p-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.patch

+diff --git a/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.out b/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.out
+index 3d6859f99..a7ffc109e 100644
+--- a/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.out
++++ b/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.out
+@@ -1,2 +1,2 @@
+ # cabal sdist
+-Wrote tarball sdist to <ROOT>/cabal.dot-uv.dist/work/./dist/sdist/p-0.1.tar.gz
++Wrote tarball sdist to <ROOT>/cabal.dot-uv.dist/work/./dist/sdist/uv-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.project

+packages: .

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.test.hs

+import Test.Cabal.Prelude
+
+-- cabal.dot-uv.project has "packages: .". That package is uv.cabal but "cabal
+-- sdist" writes sdist/p-0.1.tar.gz instead of the expected sdist/uv-0.1.tar.gz.
+-- That is wrong, "cabal sdist" should respect the "--project-file" option but
+-- instead probes the parent directory and picks up "../cabal.project" that has
+-- "packages: Projects-Default-No/p".
+--
+-- TODO: Fix this behaviour and apply the patch cabal.dot-uv.patch to update the
+-- expected output to what we'd expect if "cabal sdist" respected the project.
+main = cabalTest . withProjectFile "cabal.dot-uv.project" $ do
+    cabal "sdist" ["all"]
\ No newline at end of file

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.v2.out

+# cabal v2-sdist
+Wrote tarball sdist to <ROOT>/dist-newstyle/sdist/uv-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.dot-uv.v2.test.hs

+import Test.Cabal.Prelude
+
+-- cabal.dot-uv.project has "packages: .". That package is uv.cabal and "cabal
+-- v2-sdist" writes sdist/uv-0.1.tar.gz. This is correct.
+main = cabalTest . withProjectFile "cabal.dot-uv.project" $ do
+    cabal "v2-sdist" ["all"]
\ No newline at end of file

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.ignore-project.out

+# cabal sdist
+Wrote tarball sdist to <ROOT>/cabal.ignore-project.dist/work/./dist/sdist/uv-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.ignore-project.test.hs

+import Test.Cabal.Prelude
+
+-- This test correctly writes sdist/uv-0.1.tar.gz for the uv.cabal package.
+main = cabalTest $ do
+    cabal "sdist" ["all", "--ignore-project"]
\ No newline at end of file

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.ignore-project.v2.out

+# cabal v2-sdist
+Wrote tarball sdist to /home/philderbeast/dev/src/cabalism/cabal/cabal-testsuite/PackageTests/SDist/Respect-Project-File/dist-newstyle/sdist/p-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.ignore-project.v2.test.hs

+import Test.Cabal.Prelude
+
+-- This test should have written sdist/uv-0.1.tar.gz for the uv.cabal package
+-- but instead it probed up the directory tree, found a default cabal.project
+-- and wrote sdist/p-0.1.tar.gz. That is incorrect. It didn't ignore the
+-- project.
+main = cabalTest $ do
+    cabal "v2-sdist" ["all", "--ignore-project"]
\ No newline at end of file

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.no-project.out

+# cabal sdist
+Wrote tarball sdist to <ROOT>/cabal.no-project.dist/work/./dist/sdist/p-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.no-project.test.hs

+import Test.Cabal.Prelude
+
+-- When no project is given, "cabal sdist" probes up the directory tree, finds a
+-- default cabal.project and writes sdist/p-0.1.tar.gz. That is acceptable. An
+-- alternative and reasonable expectation (but not the behaviour seen) is that
+-- project probing would not occur and "cabal sdist" would work on the local
+-- uv.cabal package.
+main = cabalTest $ do
+    cabal "sdist" ["all"]
\ No newline at end of file

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.no-project.v2.out

+# cabal v2-sdist
+Wrote tarball sdist to /home/philderbeast/dev/src/cabalism/cabal/cabal-testsuite/PackageTests/SDist/Respect-Project-File/dist-newstyle/sdist/p-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.no-project.v2.test.hs

+import Test.Cabal.Prelude
+
+-- When no project is given, "cabal v2-sdist" probes up the directory tree,
+-- finds a default cabal.project and writes sdist/p-0.1.tar.gz. That is
+-- acceptable. An alternative and reasonable expectation (but not the behaviour
+-- seen) is that project probing would not occur and "cabal v2-sdist" would work
+-- on the local uv.cabal package.
+main = cabalTest $ do
+    cabal "v2-sdist" ["all"]
\ No newline at end of file

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.out

+# cabal sdist
+Wrote tarball sdist to <ROOT>/cabal.sub-pq.dist/work/./dist/sdist/p-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.patch

+diff --git a/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.out b/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.out
+index c96d15ee6..12dcc1217 100644
+--- a/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.out
++++ b/cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.out
+@@ -1,2 +1,3 @@
+ # cabal sdist
+ Wrote tarball sdist to <ROOT>/cabal.sub-pq.dist/work/./dist/sdist/p-0.1.tar.gz
++Wrote tarball sdist to <ROOT>/cabal.sub-pq.dist/work/./dist/sdist/q-0.1.tar.gz

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.project

+packages: p/ q/

cabal-testsuite/PackageTests/SDist/Respect-Project-File/Projects-Default-No/cabal.sub-pq.test.hs

+import Test.Cabal.Prelude
+
+-- cabal.sub-pq.project has "packages: p/ q/" but "cabal sdist" only writes
+-- sdist/p-0.1.tar.gz instead of the expected sdist/p-0.1.tar.gz and
+-- sdist/q-0.1.tar.gz. That is wrong, "cabal sdist" should respect the
+-- "--project-file" option but instead probes the parent directory and picks up
+-- "../cabal.project" that has "packages: Projects-Default-No/p".
+--
+-- TODO: Fix this behaviour and apply the patch cabal.sub-pq.patch to update the
+-- expected output to what we'd expect if "cabal sdist" respected the project.
+main = cabalTest . withProjectFile "cabal.sub-pq.project" $ do
+    cabal "sdist" ["all"]
\ No newline at end of file