test: Handle usernamePassword within withCredentials

This is useful for internal images which need to retrieve resources protected
by HTTP Basic Auth.
Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

test/groovy/JenkinsfileTest.groovy

@@ -62,6 +62,23 @@ class CurrentBuildMock extends LinkedHashMap {
 }
 
 class JenkinsfileTest extends BasePipelineTest {
+    static def withCredentialsInterceptor = { list, closure ->
+        list.forEach {
+            def vars = it instanceof List ? it : [ it ]
+            vars.forEach {
+                    binding.setVariable(it, "$it")
+                }
+        }
+        def res = closure.call()
+        list.forEach {
+            def vars = it instanceof List ? it : [ it ]
+            vars.forEach {
+                    binding.setVariable(it, null)
+                }
+        }
+        return res
+    }
+
     @Override
     @Before
     void setUp() throws Exception {
@@ -70,9 +87,11 @@ class JenkinsfileTest extends BasePipelineTest {
             assert params.versionNumberString == '${BUILD_DATE_FORMATTED,"yyyyMMdd"}.${BUILDS_TODAY_Z}'
             return "20190401.0"
         })
+        helper.registerAllowedMethod("withCredentials", [ List.class, Closure.class], withCredentialsInterceptor)
         helper.registerAllowedMethod("parameters", [ArrayList.class], null)
         helper.registerAllowedMethod("writeFile", [Map.class], null)
         helper.registerAllowedMethod("file", [Map.class], {m -> m.variable})
+        helper.registerAllowedMethod("usernamePassword", [Map.class], {m -> [m.usernameVariable, m.passwordVariable]})
         helper.registerAllowedMethod("sshagent", [Map.class, Closure.class], null)
         helper.registerAllowedMethod("deleteDir", [], null)
         helper.registerAllowedMethod("git", [Map.class], null)