JS: Add test for use steps

javascript/ql/test/ApiGraphs/custom-use-steps/VerifyAssertions.ql

@@ -0,0 +1,13 @@
+import ApiGraphs.VerifyAssertions
+private import semmle.javascript.dataflow.internal.PreCallGraphStep
+
+class CustomUseStep extends PreCallGraphStep {
+  override predicate loadStep(DataFlow::Node pred, DataFlow::Node succ, string prop) {
+    exists(DataFlow::CallNode call |
+      call.getCalleeName() = "customLoad" and
+      pred = call.getArgument(0) and
+      succ = call and
+      prop = call.getArgument(1).getStringValue()
+    )
+  }
+}

javascript/ql/test/ApiGraphs/custom-use-steps/index.js

@@ -0,0 +1,4 @@
+const foo = require("foo");
+
+foo.bar; // use=moduleImport("foo").getMember("exports").getMember("bar")
+customLoad(foo, "baz") // use=moduleImport("foo").getMember("exports").getMember("baz")

javascript/ql/test/ApiGraphs/custom-use-steps/package.json

@@ -0,0 +1,3 @@
+{
+    "name": "custom-use-steps"
+}