1 files changed, 127 insertions, 0 deletions

diff --git a/spec/ruby/core/kernel/catch_spec.rb b/spec/ruby/core/kernel/catch_spec.rb
new file mode 100644
index 0000000000..9f02303678
--- /dev/null
+++ b/spec/ruby/core/kernel/catch_spec.rb
@@ -0,0 +1,127 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Kernel.catch" do
+  before :each do
+    ScratchPad.clear
+  end
+
+  it "executes its block and catches a thrown value matching its argument" do
+    catch :thrown_key do
+      ScratchPad.record :catch_block
+      throw :thrown_key
+      ScratchPad.record :throw_failed
+    end
+    ScratchPad.recorded.should == :catch_block
+  end
+
+  it "returns the second value passed to throw" do
+    catch(:thrown_key) { throw :thrown_key, :catch_value }.should == :catch_value
+  end
+
+  it "returns the last expression evaluated if throw was not called" do
+    catch(:thrown_key) { 1; :catch_block }.should == :catch_block
+  end
+
+  it "passes the given symbol to its block" do
+    catch :thrown_key do |tag|
+      ScratchPad.record tag
+    end
+    ScratchPad.recorded.should == :thrown_key
+  end
+
+  it "raises an ArgumentError if a Symbol is thrown for a String catch value" do
+    -> { catch("exit") { throw :exit } }.should.raise(ArgumentError)
+  end
+
+  it "raises an ArgumentError if a String with different identity is thrown" do
+    -> { catch("exit".dup) { throw "exit".dup } }.should.raise(ArgumentError)
+  end
+
+  it "catches a Symbol when thrown a matching Symbol" do
+    catch :thrown_key do
+      ScratchPad.record :catch_block
+      throw :thrown_key
+    end
+    ScratchPad.recorded.should == :catch_block
+  end
+
+  it "catches a String when thrown a String with the same identity" do
+    key = "thrown_key"
+    catch key do
+      ScratchPad.record :catch_block
+      throw key
+    end
+    ScratchPad.recorded.should == :catch_block
+  end
+
+  it "accepts an object as an argument" do
+    catch(Object.new) { :catch_block }.should == :catch_block
+  end
+
+  it "yields an object when called without arguments" do
+    catch { |tag| tag }.should.instance_of?(Object)
+  end
+
+  it "can be used even in a method different from where throw is called" do
+    class CatchSpecs
+      def self.throwing_method
+        throw :blah, :thrown_value
+      end
+      def self.catching_method
+        catch :blah do
+          throwing_method
+        end
+      end
+    end
+    CatchSpecs.catching_method.should == :thrown_value
+  end
+
+  describe "when nested" do
+    before :each do
+      ScratchPad.record []
+    end
+
+    it "catches across invocation boundaries" do
+      catch :one do
+        ScratchPad << 1
+        catch :two do
+          ScratchPad << 2
+          catch :three do
+            ScratchPad << 3
+            throw :one
+            ScratchPad << 4
+          end
+          ScratchPad << 5
+        end
+        ScratchPad << 6
+      end
+
+      ScratchPad.recorded.should == [1, 2, 3]
+    end
+
+    it "catches in the nested invocation with the same key object" do
+      catch :thrown_key do
+        ScratchPad << 1
+        catch :thrown_key do
+          ScratchPad << 2
+          throw :thrown_key
+          ScratchPad << 3
+        end
+        ScratchPad << 4
+      end
+
+      ScratchPad.recorded.should == [1, 2, 4]
+    end
+  end
+
+  it "raises LocalJumpError if no block is given" do
+    -> { catch :blah }.should.raise(LocalJumpError)
+  end
+end
+
+describe "Kernel#catch" do
+  it "is a private method" do
+    Kernel.private_instance_methods(false).should.include?(:catch)
+  end
+end