unikernel/duniverse/dune_/test/blackbox-tests/test-cases/lang-dune-warning.t

@@ -0,0 +1,54 @@
+If (lang dune) does not use a valid format on a 2.x project, a warning is
+emitted:
+
+  $ cat > dune-project << EOF
+  > (lang dune 2.3.0)
+  > EOF
+
+  $ dune build
+  File "dune-project", line 1, characters 11-16:
+  1 | (lang dune 2.3.0)
+                 ^^^^^
+  Warning: The ".0" part is ignored here.
+  This version is parsed as just 2.3.
+
+  $ cat > dune-project << EOF
+  > (lang dune 2.4suffix)
+  > EOF
+
+  $ dune build
+  File "dune-project", line 1, characters 11-20:
+  1 | (lang dune 2.4suffix)
+                 ^^^^^^^^^
+  Warning: The "suffix" part is ignored here.
+  This version is parsed as just 2.4.
+
+If the version is valid, no warning is emitted:
+
+  $ cat > dune-project << EOF
+  > (lang dune 2.2)
+  > EOF
+
+  $ dune build
+
+Starting with lang 3.0, the warning turns into an error.
+
+  $ cat > dune-project << EOF
+  > (lang dune 3.0suffix)
+  > EOF
+
+  $ dune build
+  File "dune-project", line 1, characters 11-20:
+  1 | (lang dune 3.0suffix)
+                 ^^^^^^^^^
+  Error: The "suffix" part is ignored here.
+  This version is parsed as just 3.0.
+  [1]
+
+And without suffix it is accepted.
+
+  $ cat > dune-project << EOF
+  > (lang dune 3.0)
+  > EOF
+
+  $ dune build