test: translation of depopts field (#9432)

Signed-off-by: Ali Caglayan <[email protected]>

test/blackbox-tests/test-cases/pkg/depopts/opam-package-with-depopts.t

@@ -0,0 +1,38 @@
+We test how opam files with depopts fields are translated into dune.lock files:
+
+  $ . ../helpers.sh
+  $ mkrepo
+
+Make a package with a depopts field
+  $ mkpkg with-depopts <<'EOF'
+  > depopts: [ "foo" ]
+  > EOF
+  $ mkpkg foo
+
+  $ solve with-depopts
+  Solution for dune.lock:
+  - with-depopts.0.0.1
+
+When depopts are supported and selected, the above lock should change and we
+should also be able to see a deps field in the lock file:
+
+  $ cat dune.lock/with-depopts.pkg
+  (version 0.0.1)
+
+We should also be able to validate the lock directory:
+
+  $ dune pkg validate-lockdir
+
+Depopts should not be selected if they conflict with other constraints:
+
+  $ mkpkg no-foo <<'EOF'
+  > depends: [ "with-depopts" ]
+  > conflicts: [ "foo" ]
+  > EOF
+
+  $ solve no-foo
+  Solution for dune.lock:
+  - no-foo.0.0.1
+  - with-depopts.0.0.1
+
+  $ dune pkg validate-lockdir