cmd/cue: add kubernetes semantics test

We are currently generating "wrong" schemas from K8s source when
comparing against their OpenAPI spec.

Change-Id: Ieb30f98ba2bdc921ab48c81aedbdc89c685b4bd9
Signed-off-by: Tim Windelschmidt <[email protected]>

Author: fionera

cmd/cue/cmd/testdata/script/get_go_types_kubernetes.txtar

@@ -0,0 +1,52 @@
+# Test that a get go works for kubernetes types,
+# including those special cases that result in _ and string
+# that are specifically mentioned in help get go.
+
+exec cue get go --local ./...
+cmp ./file2_go_gen.cue ./file2_go_gen.cue.golden
+
+-- go.mod --
+module mod.test
+
+go 1.21
+-- cue.mod/module.cue --
+module: "mod.test"
+-- file1.go --
+package pkg1
+
+// +k8s:openapi-gen=true
+-- file2.go --
+package pkg1
+
+type Foo struct {
+	Required string `json:"required"`
+	Pointer *string `json:"pointer"`
+	OmitEmptyPointer *string `json:"omitEmptyPointer,omitempty"`
+	// +optional
+    OptionalComment string `json:"optionalComment"`
+	// +optional
+    OptionalCommentPointer *string `json:"optionalCommentPointer"`
+	// +nullable
+    NullableCommentPointer *string `json:"nullableCommentPointer"`
+}
+-- file2_go_gen.cue.golden --
+// Code generated by cue get go. DO NOT EDIT.
+
+//cue:generate cue get go mod.test
+
+package pkg1
+
+#Foo: {
+	required:          string        @go(Required)
+	pointer?:          null | string @go(Pointer,*string)
+	omitEmptyPointer?: null | string @go(OmitEmptyPointer,*string)
+
+	// +optional
+	optionalComment?: string @go(OptionalComment)
+
+	// +optional
+	optionalCommentPointer?: null | string @go(OptionalCommentPointer,*string)
+
+	// +nullable
+	nullableCommentPointer?: null | string @go(NullableCommentPointer,*string)
+}