1 files changed, 80 insertions, 0 deletions
diff --git a/spec/bundler/bundler/environment_preserver_spec.rb b/spec/bundler/bundler/environment_preserver_spec.rb
new file mode 100644
index 0000000000..41d2650055
--- /dev/null
+++ b/spec/bundler/bundler/environment_preserver_spec.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+require "spec_helper"
+
+RSpec.describe Bundler::EnvironmentPreserver do
+  let(:preserver) { described_class.new(env, ["foo"]) }
+
+  describe "#backup" do
+    let(:env) { { "foo" => "my-foo", "bar" => "my-bar" } }
+    subject { preserver.backup }
+
+    it "should create backup entries" do
+      expect(subject["BUNDLER_ORIG_foo"]).to eq("my-foo")
+    end
+
+    it "should keep the original entry" do
+      expect(subject["foo"]).to eq("my-foo")
+    end
+
+    it "should not create backup entries for unspecified keys" do
+      expect(subject.key?("BUNDLER_ORIG_bar")).to eq(false)
+    end
+
+    it "should not affect the original env" do
+      subject
+      expect(env.keys.sort).to eq(%w(bar foo))
+    end
+
+    context "when a key is empty" do
+      let(:env) { { "foo" => "" } }
+
+      it "should not create backup entries" do
+        expect(subject.key?("BUNDLER_ORIG_foo")).to eq(false)
+      end
+    end
+
+    context "when an original key is set" do
+      let(:env) { { "foo" => "my-foo", "BUNDLER_ORIG_foo" => "orig-foo" } }
+
+      it "should keep the original value in the BUNDLER_ORIG_ variable" do
+        expect(subject["BUNDLER_ORIG_foo"]).to eq("orig-foo")
+      end
+
+      it "should keep the variable" do
+        expect(subject["foo"]).to eq("my-foo")
+      end
+    end
+  end
+
+  describe "#restore" do
+    subject { preserver.restore }
+
+    context "when an original key is set" do
+      let(:env) { { "foo" => "my-foo", "BUNDLER_ORIG_foo" => "orig-foo" } }
+
+      it "should restore the original value" do
+        expect(subject["foo"]).to eq("orig-foo")
+      end
+
+      it "should delete the backup value" do
+        expect(subject.key?("BUNDLER_ORIG_foo")).to eq(false)
+      end
+    end
+
+    context "when no original key is set" do
+      let(:env) { { "foo" => "my-foo" } }
+
+      it "should keep the current value" do
+        expect(subject["foo"]).to eq("my-foo")
+      end
+    end
+
+    context "when the original key is empty" do
+      let(:env) { { "foo" => "my-foo", "BUNDLER_ORIG_foo" => "" } }
+
+      it "should keep the current value" do
+        expect(subject["foo"]).to eq("my-foo")
+      end
+    end
+  end
+end