1 files changed, 20 insertions, 2 deletions
diff --git a/spec/ruby/core/env/shared/value.rb b/spec/ruby/core/env/shared/value.rb
index d9ee90f12d..c2b5025465 100644
--- a/spec/ruby/core/env/shared/value.rb
+++ b/spec/ruby/core/env/shared/value.rb
@@ -1,11 +1,29 @@
 describe :env_value, shared: true do
+  before :each do
+    @saved_foo = ENV["foo"]
+  end
+
+  after :each do
+    ENV["foo"] = @saved_foo
+  end
+
   it "returns true if ENV has the value" do
     ENV["foo"] = "bar"
     ENV.send(@method, "bar").should == true
-    ENV["foo"] = nil
   end
 
   it "returns false if ENV doesn't have the value" do
-    ENV.send(@method, "this_value_should_never_exist").should == false
+    ENV.send(@method, "foo").should == false
+  end
+
+  it "coerces the value element with #to_str" do
+    ENV["foo"] = "bar"
+    v = mock('value')
+    v.should_receive(:to_str).and_return("bar")
+    ENV.send(@method, v).should == true
+  end
+
+  it "returns nil if the argument is not a String and does not respond to #to_str" do
+    ENV.send(@method, Object.new).should == nil
   end
 end