1 files changed, 35 insertions, 0 deletions
diff --git a/spec/mspec/lib/mspec/matchers/block_caller.rb b/spec/mspec/lib/mspec/matchers/block_caller.rb
new file mode 100644
index 0000000000..5451950712
--- /dev/null
+++ b/spec/mspec/lib/mspec/matchers/block_caller.rb
@@ -0,0 +1,35 @@
+class BlockingMatcher
+  def matches?(block)
+    started = false
+    blocking = true
+
+    thread = Thread.new do
+      started = true
+      block.call
+
+      blocking = false
+    end
+
+    while !started and status = thread.status and status != "sleep"
+      Thread.pass
+    end
+    thread.kill
+    thread.join
+
+    blocking
+  end
+
+  def failure_message
+    ['Expected the given Proc', 'to block the caller']
+  end
+
+  def negative_failure_message
+    ['Expected the given Proc', 'to not block the caller']
+  end
+end
+
+class Object
+  def block_caller(timeout = 0.1)
+    BlockingMatcher.new
+  end
+end