1 files changed, 33 insertions, 2 deletions
diff --git a/spec/ruby/core/env/delete_spec.rb b/spec/ruby/core/env/delete_spec.rb
index e02adf963f..db6d07b057 100644
--- a/spec/ruby/core/env/delete_spec.rb
+++ b/spec/ruby/core/env/delete_spec.rb
@@ -1,8 +1,11 @@
-require File.expand_path('../../../spec_helper', __FILE__)
+require_relative '../../spec_helper'
 
 describe "ENV.delete" do
+  before :each do
+    @saved_foo = ENV["foo"]
+  end
   after :each do
-    ENV.delete("foo")
+    ENV["foo"] = @saved_foo
   end
 
   it "removes the variable from the environment" do
@@ -16,9 +19,37 @@ describe "ENV.delete" do
     ENV.delete("foo").should == "bar"
   end
 
+  it "returns nil if the named environment variable does not exist and no block given" do
+    ENV.delete("foo")
+    ENV.delete("foo").should == nil
+  end
+
   it "yields the name to the given block if the named environment variable does not exist" do
     ENV.delete("foo")
     ENV.delete("foo") { |name| ScratchPad.record name }
     ScratchPad.recorded.should == "foo"
   end
+
+  it "returns the result of given block if the named environment variable does not exist" do
+    ENV.delete("foo")
+    ENV.delete("foo") { |name| "bar" }.should == "bar"
+  end
+
+  it "does not evaluate the block if the environment variable exists" do
+    ENV["foo"] = "bar"
+    ENV.delete("foo") { |name| fail "Should not happen" }
+    ENV["foo"].should == nil
+  end
+
+  it "removes the variable coerced with #to_str" do
+    ENV["foo"] = "bar"
+    k = mock('key')
+    k.should_receive(:to_str).and_return("foo")
+    ENV.delete(k)
+    ENV["foo"].should == nil
+  end
+
+  it "raises TypeError if the argument is not a String and does not respond to #to_str" do
+    -> { ENV.delete(Object.new) }.should.raise(TypeError, "no implicit conversion of Object into String")
+  end
 end