Add test case for removing unused dependencies on whitelisted update

tests/Composer/Test/Fixtures/installer/update-whitelist-removes-unused.test

@@ -0,0 +1,32 @@
+--TEST--
+Update with a package whitelist removes unused packages
+--COMPOSER--
+{
+    "repositories": [
+        {
+            "type": "package",
+            "package": [
+                { "name": "whitelisted", "version": "1.1.0" },
+                { "name": "whitelisted", "version": "1.0.0", "require": { "fixed-dependency": "1.0.0", "old-dependency": "1.0.0" } },
+                { "name": "fixed-dependency", "version": "1.1.0" },
+                { "name": "fixed-dependency", "version": "1.0.0" },
+                { "name": "old-dependency", "version": "1.0.0" }
+            ]
+        }
+    ],
+    "require": {
+        "whitelisted": "1.*",
+        "fixed-dependency": "1.*"
+    }
+}
+--INSTALLED--
+[
+    { "name": "whitelisted", "version": "1.0.0", "require": { "old-dependency": "1.0.0", "fixed-dependency": "1.0.0" } },
+    { "name": "fixed-dependency", "version": "1.0.0" },
+    { "name": "old-dependency", "version": "1.0.0" }
+]
+--RUN--
+update --with-dependencies whitelisted
+--EXPECT--
+Uninstalling old-dependency (1.0.0)
+Updating whitelisted (1.0.0) to whitelisted (1.1.0)