1 files changed, 72 insertions, 0 deletions
diff --git a/spec/ruby/shared/string/start_with.rb b/spec/ruby/shared/string/start_with.rb
new file mode 100644
index 0000000000..d8d6e13f6a
--- /dev/null
+++ b/spec/ruby/shared/string/start_with.rb
@@ -0,0 +1,72 @@
+describe :start_with, shared: true do
+  # the @method should either be :to_s or :to_sym
+
+  it "returns true only if beginning match" do
+    s = "hello".send(@method)
+    s.should.start_with?('h')
+    s.should.start_with?('hel')
+    s.should_not.start_with?('el')
+  end
+
+  it "returns true only if any beginning match" do
+    "hello".send(@method).should.start_with?('x', 'y', 'he', 'z')
+  end
+
+  it "returns true if the search string is empty" do
+    "hello".send(@method).should.start_with?("")
+    "".send(@method).should.start_with?("")
+  end
+
+  it "converts its argument using :to_str" do
+    s = "hello".send(@method)
+    find = mock('h')
+    find.should_receive(:to_str).and_return("h")
+    s.should.start_with?(find)
+  end
+
+  it "ignores arguments not convertible to string" do
+    "hello".send(@method).should_not.start_with?()
+    -> { "hello".send(@method).start_with?(1) }.should raise_error(TypeError)
+    -> { "hello".send(@method).start_with?(["h"]) }.should raise_error(TypeError)
+    -> { "hello".send(@method).start_with?(1, nil, "h") }.should raise_error(TypeError)
+  end
+
+  it "uses only the needed arguments" do
+    find = mock('h')
+    find.should_not_receive(:to_str)
+    "hello".send(@method).should.start_with?("h",find)
+  end
+
+  it "works for multibyte strings" do
+    "céréale".send(@method).should.start_with?("cér")
+  end
+
+  it "supports regexps" do
+    regexp = /[h1]/
+    "hello".send(@method).should.start_with?(regexp)
+    "1337".send(@method).should.start_with?(regexp)
+    "foxes are 1337".send(@method).should_not.start_with?(regexp)
+    "chunky\n12bacon".send(@method).should_not.start_with?(/12/)
+  end
+
+  it "supports regexps with ^ and $ modifiers" do
+    regexp1 = /^\d{2}/
+    regexp2 = /\d{2}$/
+    "12test".send(@method).should.start_with?(regexp1)
+    "test12".send(@method).should_not.start_with?(regexp1)
+    "12test".send(@method).should_not.start_with?(regexp2)
+    "test12".send(@method).should_not.start_with?(regexp2)
+  end
+
+  it "sets Regexp.last_match if it returns true" do
+    regexp = /test-(\d+)/
+    "test-1337".send(@method).start_with?(regexp).should be_true
+    Regexp.last_match.should_not be_nil
+    Regexp.last_match[1].should == "1337"
+    $1.should == "1337"
+
+    "test-asdf".send(@method).start_with?(regexp).should be_false
+    Regexp.last_match.should be_nil
+    $1.should be_nil
+  end
+end