Add to-lower/to-upper

Bug: 262303006
Test: go test
Change-Id: I80af8ace90556e58676adac4cb90d5d62c5b7b96

mk2rbc/mk2rbc_test.go

@@ -1659,6 +1659,26 @@ def init(g, handle):
   g["X"] = "%s Y" % g.get("A", "") or g["B"]
   g["D"] = rblf.expand_wildcard("*.mk")
   g["X"] = rblf.mk2rbc_error("product.mk:12", "Expected all arguments to $(or) or $(and) to have the same type, found \"string\" and \"list\"")
+`,
+	},
+	{
+
+		desc:   "is-lower/is-upper",
+		mkname: "product.mk",
+		in: `
+X := $(call to-lower,aBc)
+X := $(call to-upper,aBc)
+X := $(call to-lower,$(VAR))
+X := $(call to-upper,$(VAR))
+`,
+		expected: `load("//build/make/core:product_config.rbc", "rblf")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+  g["X"] = ("aBc").lower()
+  g["X"] = ("aBc").upper()
+  g["X"] = (g.get("VAR", "")).lower()
+  g["X"] = (g.get("VAR", "")).upper()
 `,
 	},
 }