diff --git a/tests/Composer/Test/Fixtures/installer/conflict-with-alias-does-not-prevent-installation-if-not-required.test b/tests/Composer/Test/Fixtures/installer/conflict-on-root-with-alias-does-not-prevent-update-if-not-required.test
similarity index 73%
rename from tests/Composer/Test/Fixtures/installer/conflict-with-alias-does-not-prevent-installation-if-not-required.test
rename to tests/Composer/Test/Fixtures/installer/conflict-on-root-with-alias-does-not-prevent-update-if-not-required.test
index 542a883f2..454384206 100644
--- a/tests/Composer/Test/Fixtures/installer/conflict-with-alias-does-not-prevent-installation-if-not-required.test
+++ b/tests/Composer/Test/Fixtures/installer/conflict-on-root-with-alias-does-not-prevent-update-if-not-required.test
@@ -27,6 +27,22 @@ and we don't want to modify branch alias meta data in the lock file.
 }
 --RUN--
 update
+--EXPECT-LOCK--
+{
+    "packages": [
+        { "name": "some/dep", "version": "dev-main", "type": "library", "extra": {"branch-alias": {"dev-main": "1.3.x-dev"} } }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {
+        "some/dep": 20
+    },
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": []
+}
 --EXPECT--
 Installing some/dep (dev-main)
-Marking some/dep (1.3.x-dev) as installed, alias of some/dep (dev-main)'
+Marking some/dep (1.3.x-dev) as installed, alias of some/dep (dev-main)
diff --git a/tests/Composer/Test/Fixtures/installer/conflict-with-alias-does-not-prevent-update-if-not-required.test b/tests/Composer/Test/Fixtures/installer/conflict-with-alias-does-not-prevent-update-if-not-required.test
new file mode 100644
index 000000000..e03cd0f2a
--- /dev/null
+++ b/tests/Composer/Test/Fixtures/installer/conflict-with-alias-does-not-prevent-update-if-not-required.test
@@ -0,0 +1,45 @@
+--TEST--
+Test that conflict on a branch alias is ignored if the alias is not required for installation.
+--COMPOSER--
+{
+    "repositories": [
+        {
+            "type": "package",
+            "package": [
+                { "name": "some/dep", "version": "1.0.0" },
+                { "name": "some/dep", "version": "1.1.0" },
+                { "name": "some/dep", "version": "1.2.0" },
+                { "name": "some/dep", "version": "dev-main", "extra": {"branch-alias": {"dev-main": "1.3.x-dev"} } },
+                { "name": "some/dep", "version": "1.2.x-dev" },
+                { "name": "conflictor/foo", "version": "1.0.0", "conflict": { "some/dep": ">=1.3" } }
+            ]
+        }
+    ],
+    "require": {
+        "some/dep": "dev-main",
+        "conflictor/foo": "1.0.0"
+    }
+}
+--RUN--
+update
+--EXPECT-LOCK--
+{
+    "packages": [
+        { "name": "conflictor/foo", "version": "1.0.0", "conflict": { "some/dep": ">=1.3" }, "type": "library" },
+        { "name": "some/dep", "version": "dev-main", "extra": {"branch-alias": {"dev-main": "1.3.x-dev"} }, "type": "library" }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {
+        "some/dep": 20
+    },
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": []
+}
+--EXPECT--
+Installing conflictor/foo (1.0.0)
+Installing some/dep (dev-main)
+Marking some/dep (1.3.x-dev) as installed, alias of some/dep (dev-main)
diff --git a/tests/Composer/Test/Fixtures/installer/conflict-with-alias-in-lock-does-not-prevent-install-if-not-required.test b/tests/Composer/Test/Fixtures/installer/conflict-with-alias-in-lock-does-not-prevent-install-if-not-required.test
new file mode 100644
index 000000000..c6f91e115
--- /dev/null
+++ b/tests/Composer/Test/Fixtures/installer/conflict-with-alias-in-lock-does-not-prevent-install-if-not-required.test
@@ -0,0 +1,45 @@
+--TEST--
+Test that conflict on a branch alias is ignored if the alias is not required for installation.
+--COMPOSER--
+{
+    "repositories": [
+        {
+            "type": "package",
+            "package": [
+                { "name": "some/dep", "version": "1.0.0" },
+                { "name": "some/dep", "version": "1.1.0" },
+                { "name": "some/dep", "version": "1.2.0" },
+                { "name": "some/dep", "version": "dev-main", "extra": {"branch-alias": {"dev-main": "1.3.x-dev"} } },
+                { "name": "some/dep", "version": "1.2.x-dev" },
+                { "name": "conflictor/foo", "version": "1.0.0", "conflict": { "some/dep": ">=1.3" } }
+            ]
+        }
+    ],
+    "require": {
+        "some/dep": "dev-main",
+        "conflictor/foo": "1.0.0"
+    }
+}
+--LOCK--
+{
+    "packages": [
+        { "name": "conflictor/foo", "version": "1.0.0", "conflict": { "some/dep": ">=1.3" }, "type": "library" },
+        { "name": "some/dep", "version": "dev-main", "extra": {"branch-alias": {"dev-main": "1.3.x-dev"} }, "type": "library" }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {
+        "some/dep": 20
+    },
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": []
+}
+--RUN--
+install
+--EXPECT--
+Installing conflictor/foo (1.0.0)
+Installing some/dep (dev-main)
+Marking some/dep (1.3.x-dev) as installed, alias of some/dep (dev-main)
diff --git a/tests/Composer/Test/Fixtures/installer/conflict-with-alias-prevents-installation.test b/tests/Composer/Test/Fixtures/installer/conflict-with-alias-prevents-update.test
similarity index 67%
rename from tests/Composer/Test/Fixtures/installer/conflict-with-alias-prevents-installation.test
rename to tests/Composer/Test/Fixtures/installer/conflict-with-alias-prevents-update.test
index b4425a6eb..74b61304e 100644
--- a/tests/Composer/Test/Fixtures/installer/conflict-with-alias-prevents-installation.test
+++ b/tests/Composer/Test/Fixtures/installer/conflict-with-alias-prevents-update.test
@@ -23,5 +23,21 @@ Test that conflict on a branch alias is respected
 }
 --RUN--
 update
+--EXPECT-LOCK--
+{
+    "packages": [
+        { "name": "some/dep", "version": "1.2.x-dev", "type": "library" }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {
+        "some/dep": 20
+    },
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": []
+}
 --EXPECT--
 Installing some/dep (1.2.x-dev)