add integration test

integration/dockerfiles/Dockerfile_test_issue_3429

@@ -0,0 +1,13 @@
+FROM ubuntu
+
+RUN mkdir /test \
+    && ln -s /test /link
+
+# Fails on main@1d2bff5 before #3429: On the second run,
+# when extracting from cache, we first delete the /test directory
+# and thereafter fail to replace the link with a directory.
+# The link is now broken and 'stat' returns an error.
+# On build this works as we first delete the link,
+# and only thereafter create the directory.
+RUN rm -rf /test /link \
+    && mkdir /link

integration/images.go

@@ -218,6 +218,7 @@ func NewDockerFileBuilder() *DockerFileBuilder {
 		"Dockerfile_test_cache_install": {},
 		"Dockerfile_test_cache_perm":    {},
 		"Dockerfile_test_cache_copy":    {},
+		"Dockerfile_test_issue_3429":    {},
 	}
 	d.TestOCICacheDockerfiles = map[string]struct{}{
 		"Dockerfile_test_cache_oci":         {},