Remove Gemfile.lock (it is far too volatile for VCS now)

test/tests/ruby-bundler/Gemfile.lock

@@ -1,33 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    diff-lcs (1.2.5)
-    mini_portile (0.6.2)
-    nokogiri (1.6.5)
-      mini_portile (~> 0.6.0)
-    nokogiri (1.6.5-java)
-    rack (1.6.0)
-    rspec (3.1.0)
-      rspec-core (~> 3.1.0)
-      rspec-expectations (~> 3.1.0)
-      rspec-mocks (~> 3.1.0)
-    rspec-core (3.1.7)
-      rspec-support (~> 3.1.0)
-    rspec-expectations (3.1.2)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.1.0)
-    rspec-mocks (3.1.3)
-      rspec-support (~> 3.1.0)
-    rspec-support (3.1.2)
-
-PLATFORMS
-  java
-  ruby
-
-DEPENDENCIES
-  nokogiri
-  rack (~> 1.1)
-  rspec
-
-BUNDLED WITH
-   1.10.3

test/tests/ruby-bundler/container.sh

@@ -1,4 +1,14 @@
 #!/bin/bash
 set -e
 
+dir="$(mktemp -d)"
+trap "rm -rf '$dir'" EXIT
+
+cp Gemfile "$dir"
+
+# make sure that running "bundle" twice doesn't change Gemfile.lock the second time
+cd "$dir"
 bundle
+cp Gemfile.lock{,.orig}
+bundle
+diff -u Gemfile.lock{.orig,} >&2