diff --git a/spec/spectator/dsl/mocks/double_spec.cr b/spec/spectator/dsl/mocks/double_spec.cr
index a61173e..5622f63 100644
--- a/spec/spectator/dsl/mocks/double_spec.cr
+++ b/spec/spectator/dsl/mocks/double_spec.cr
@@ -32,6 +32,28 @@ Spectator.describe "Double DSL" do
         expect { dbl.baz(:xyz, 123, a: "XYZ") }.to raise_error(Spectator::UnexpectedMessage, /\(:xyz, 123, a: "XYZ"\)/)
       end
     end
+
+    context "blocks" do
+      it "supports blocks" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to eq("foobar")
+          expect(dbl.bar { nil }).to eq(42)
+        end
+      end
+
+      it "supports blocks and has non-union return types" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to compile_as(String)
+          expect(dbl.bar { nil }).to compile_as(Int32)
+        end
+      end
+
+      it "fails on undefined messages" do
+        expect do
+          dbl.baz { nil }
+        end.to raise_error(Spectator::UnexpectedMessage, /baz/)
+      end
+    end
   end
 
   context "block with stubs" do
@@ -143,6 +165,28 @@ Spectator.describe "Double DSL" do
         expect(dbl.baz(42)).to eq("block2")
       end
     end
+
+    context "methods accepting blocks" do
+      double(:test7) do
+        stub def foo
+          yield
+        end
+
+        stub def bar(& : Int32 -> String)
+          yield 42
+        end
+      end
+
+      subject(dbl) { double(:test7) }
+
+      it "defines the method and yields" do
+        expect(dbl.foo { :xyz }).to eq(:xyz)
+      end
+
+      it "matches methods with block argument type restrictions" do
+        expect(dbl.bar &.to_s).to eq("42")
+      end
+    end
   end
 
   describe "double naming" do
diff --git a/spec/spectator/dsl/mocks/null_double_spec.cr b/spec/spectator/dsl/mocks/null_double_spec.cr
index 43a7d51..013eb1f 100644
--- a/spec/spectator/dsl/mocks/null_double_spec.cr
+++ b/spec/spectator/dsl/mocks/null_double_spec.cr
@@ -28,6 +28,26 @@ Spectator.describe "Null double DSL" do
     it "returns self for unexpected messages" do
       expect_null_double(dbl, dbl.baz)
     end
+
+    context "blocks" do
+      it "supports blocks" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to eq("foobar")
+          expect(dbl.bar { nil }).to eq(42)
+        end
+      end
+
+      it "supports blocks and has non-union return types" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to compile_as(String)
+          expect(dbl.bar { nil }).to compile_as(Int32)
+        end
+      end
+
+      it "returns self on undefined messages" do
+        expect_null_double(dbl, dbl.baz { nil })
+      end
+    end
   end
 
   context "block with stubs" do
@@ -139,5 +159,27 @@ Spectator.describe "Null double DSL" do
         expect(dbl.baz(42)).to eq("block2")
       end
     end
+
+    context "methods accepting blocks" do
+      double(:test7) do
+        stub def foo
+          yield
+        end
+
+        stub def bar(& : Int32 -> String)
+          yield 42
+        end
+      end
+
+      subject(dbl) { double(:test7).as_null_object }
+
+      it "defines the method and yields" do
+        expect(dbl.foo { :xyz }).to eq(:xyz)
+      end
+
+      it "matches methods with block argument type restrictions" do
+        expect(dbl.bar &.to_s).to eq("42")
+      end
+    end
   end
 end
diff --git a/spec/spectator/mocks/double_spec.cr b/spec/spectator/mocks/double_spec.cr
index f6db87d..7204863 100644
--- a/spec/spectator/mocks/double_spec.cr
+++ b/spec/spectator/mocks/double_spec.cr
@@ -39,8 +39,26 @@ Spectator.describe Spectator::Double do
       expect { dbl.baz }.to compile_as(Nil)
     end
 
-    it "supports blocks" do
-      dbl.bar
+    context "blocks" do
+      it "supports blocks" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to eq(42)
+          expect(dbl.bar { nil }).to eq("baz")
+        end
+      end
+
+      it "supports blocks and has non-union return types" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to compile_as(Int32)
+          expect(dbl.bar { nil }).to compile_as(String)
+        end
+      end
+
+      it "fails on undefined messages" do
+        expect do
+          dbl.baz { nil }
+        end.to raise_error(Spectator::UnexpectedMessage, /baz/)
+      end
     end
   end
 
@@ -208,6 +226,7 @@ Spectator.describe Spectator::Double do
     context "without common object methods" do
       Spectator::Double.define(TestDouble) do
         abstract_stub abstract def foo(value) : String
+        abstract_stub abstract def foo(value, & : -> _) : String
       end
 
       let(stub) { Spectator::ValueStub.new(:foo, "bar", arguments).as(Spectator::Stub) }
@@ -228,6 +247,10 @@ Spectator.describe Spectator::Double do
       it "has a non-union return type" do
         expect(dbl.foo("foobar")).to compile_as(String)
       end
+
+      it "ignores the block argument if not in the constraint" do
+        expect(dbl.foo("foobar") { nil }).to eq("bar")
+      end
     end
 
     context "with common object methods" do
@@ -291,5 +314,14 @@ Spectator.describe Spectator::Double do
         expect(dbl.foo(:lucky)).to eq(7)
       end
     end
+
+    it "ignores the block argument if not in the constraint" do
+      dbl._spectator_define_stub(stub5)
+      dbl._spectator_define_stub(stub7)
+      aggregate_failures do
+        expect(dbl.foo { nil }).to eq(5)
+        expect(dbl.foo(:lucky) { nil }).to eq(7)
+      end
+    end
   end
 end
diff --git a/spec/spectator/mocks/null_double_spec.cr b/spec/spectator/mocks/null_double_spec.cr
index 134f0e0..3e41110 100644
--- a/spec/spectator/mocks/null_double_spec.cr
+++ b/spec/spectator/mocks/null_double_spec.cr
@@ -32,6 +32,26 @@ Spectator.describe Spectator::NullDouble do
         expect(dbl.bar).to compile_as(String)
       end
     end
+
+    context "blocks" do
+      it "supports blocks" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to eq(42)
+          expect(dbl.bar { nil }).to eq("baz")
+        end
+      end
+
+      it "supports blocks and has non-union return types" do
+        aggregate_failures do
+          expect(dbl.foo { nil }).to compile_as(Int32)
+          expect(dbl.bar { nil }).to compile_as(String)
+        end
+      end
+
+      it "returns self on undefined messages" do
+        expect_null_double(dbl, dbl.baz { nil })
+      end
+    end
   end
 
   context "with abstract stubs and return type annotations" do
@@ -168,6 +188,7 @@ Spectator.describe Spectator::NullDouble do
     context "without common object methods" do
       Spectator::NullDouble.define(TestDouble) do
         abstract_stub abstract def foo(value)
+        abstract_stub abstract def foo(value, & : -> _)
       end
 
       let(stub) { Spectator::ValueStub.new(:foo, "bar", arguments).as(Spectator::Stub) }
@@ -184,6 +205,10 @@ Spectator.describe Spectator::NullDouble do
       it "returns self when argument count doesn't match" do
         expect_null_double(dbl, dbl.foo)
       end
+
+      it "ignores the block argument if not in the constraint" do
+        expect(dbl.foo("foobar") { nil }).to eq("bar")
+      end
     end
 
     context "with common object methods" do
@@ -243,5 +268,14 @@ Spectator.describe Spectator::NullDouble do
         expect(dbl.foo(:lucky)).to eq(7)
       end
     end
+
+    it "ignores the block argument if not in the constraint" do
+      dbl._spectator_define_stub(stub5)
+      dbl._spectator_define_stub(stub7)
+      aggregate_failures do
+        expect(dbl.foo { nil }).to eq(5)
+        expect(dbl.foo(:lucky) { nil }).to eq(7)
+      end
+    end
   end
 end