cmd/cue/cmd: verify issue 322 is fixed

Fixes #322

Change-Id: I026d67997e5daec4e833ea75ccf64ec1f965abeb
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/7067
Reviewed-by: CUE cueckoo <[email protected]>
Reviewed-by: Marcel van Lohuizen <[email protected]>

Author: mpvl

cmd/cue/cmd/testdata/script/issue322.txt

@@ -0,0 +1,16 @@
+! cue vet
+cmp stderr expect-stderr
+
+-- expect-stderr --
+imported and not used: "strings":
+    ./x.cue:2:8
+-- x.cue --
+package x
+import "strings"
+
+foo: "hello"
+
+-- y.cue --
+package x
+
+bar: foo