Add test for addTarget selector.

Author: ileitch

Tests/XcodeTests/iOSProject/iOSProject/XibViewController.swift

@@ -8,10 +8,12 @@ class XibViewController: UIViewController {
 
     override func viewDidLoad() {
         super.viewDidLoad()
-        _ = #selector(targetMethod)
+        _ = #selector(selectorMethod)
+        button.addTarget(self, action: #selector(addTargetMethod), for: .touchUpInside)
     }
 
-    @objc private func targetMethod() {}
+    @objc private func selectorMethod() {}
+    @objc private func addTargetMethod() {}
 }
 
 struct XibViewControllerWrapper: UIViewControllerRepresentable {

Tests/XcodeTests/iOSProjectTest.swift

@@ -90,7 +90,8 @@ class iOSProjectTest: SourceGraphTestCase {
     #endif
 
     func testRetainsMethodReferencedByObjcSelector() {
-        XCTAssertReferenced((.functionMethodInstance, "targetMethod()"), descendentOf: (.class, "XibViewController"))
+        XCTAssertReferenced((.functionMethodInstance, "selectorMethod()"), descendentOf: (.class, "XibViewController"))
+        XCTAssertReferenced((.functionMethodInstance, "addTargetMethod()"), descendentOf: (.class, "XibViewController"))
     }
 
     func testMultiTargetFile() {