message: Updated test to ensure cargo update transforms Cargo.lock
diff: @@ -10,7 +10,7 @@ use hamcrest::assert_that;
  fn oldest_lockfile_still_works() {
  Package::new("foo", "0.1.0").publish();
  - let expected_lock_file =
  + let expected_lockfile =
  r#"[[package]]
  name = "bar"
  version = "0.0.1"
  @@ -27,7 +27,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
  "checksum foo 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "[..]"
  "#;
  - let lockfile = r#"
  + let old_lockfile = r#"
  [root]
  name = "bar"
  version = "0.0.1"
  @@ -52,18 +52,25 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
  foo = "0.1.0"
  "#)
  .file("src/lib.rs", "")
  - .file("Cargo.lock", lockfile);
  + .file("Cargo.lock", old_lockfile);
  p.build();
  - assert_that(p.cargo("build"),
  + let cargo_commands = vec![
  + "build",
  + "update"
  + ];
  +
  + for cargo_command in cargo_commands {
  + assert_that(p.cargo(cargo_command),
  execs().with_status(0));
  let lock = p.read_lockfile();
  - for (l, r) in expected_lock_file.lines().zip(lock.lines()) {
  + for (l, r) in expected_lockfile.lines().zip(lock.lines()) {
  assert!(lines_match(l, r), "Lines differ:\n{}\n\n{}", l, r);
  }
  - assert_eq!(lock.lines().count(), expected_lock_file.lines().count());
  + assert_eq!(lock.lines().count(), expected_lockfile.lines().count());
  + }
  }
  #[test]
  