Add spec for IO#expect

spec/ruby/library/expect/expect_spec.rb

@@ -0,0 +1,60 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require 'expect'
+
+describe "IO#expect" do
+  before :each do
+    @read, @write = IO.pipe
+  end
+
+  after :each do
+    @read.close unless @read.closed?
+    @write.close unless @write.closed?
+  end
+
+  it "matches data against a Regexp" do
+    @write << "prompt> hello"
+
+    result = @read.expect(/[pf]rompt>/)
+    result.should == ["prompt>"]
+  end
+
+  it "matches data against a String" do
+    @write << "prompt> hello"
+
+    result = @read.expect("prompt>")
+    result.should == ["prompt>"]
+  end
+
+  it "returns any captures of the Regexp" do
+    @write << "prompt> hello"
+
+    result = @read.expect(/(pro)mpt(>)/)
+    result.should == ["prompt>", "pro", ">"]
+  end
+
+  it "returns raises IOError if the IO is closed" do
+    @write << "prompt> hello"
+    @read.close
+
+    lambda {
+      @read.expect("hello")
+    }.should raise_error(IOError)
+  end
+
+  it "returns nil if eof is hit" do
+    @write << "pro"
+    @write.close
+
+    @read.expect("prompt").should be_nil
+  end
+
+  it "yields the result if a block is given" do
+    @write << "prompt> hello"
+
+    res = nil
+
+    @read.expect("prompt>") { |x| res = x }
+
+    res.should == ["prompt>"]
+  end
+end