Add test

Author: smowton

go/ql/test/library-tests/semmle/go/dataflow/MapReadsAndStores/Flows.expected

@@ -0,0 +1,3 @@
+import go
+import TestUtilities.InlineFlowTest
+import DefaultFlowTest

go/ql/test/library-tests/semmle/go/dataflow/MapReadsAndStores/Flows.ql

@@ -0,0 +1,17 @@
+package main
+
+func source() string {
+	return "untrusted data"
+}
+
+func sink(any) {
+}
+
+func main() {
+	var someMap map[string]string = map[string]string{}
+	someMap["someKey"] = source()
+
+	for _, val := range someMap {
+		sink(val) // $ hasValueFlow="val"
+	}
+}