Support free variables in mocked types

spec/issues/github_issue_48_spec.cr

@@ -0,0 +1,46 @@
+require "../spec_helper"
+
+Spectator.describe "GitHub Issue #48" do
+  class Test
+    def return_this(thing : T) : T forall T
+      thing
+    end
+
+    def map(thing : T, & : T -> U) : U forall T, U
+      yield thing
+    end
+
+    def make_nilable(thing : T) : T? forall T
+      thing.as(T?)
+    end
+  end
+
+  mock Test, make_nilable: nil
+
+  let(fake) { mock(Test) }
+
+  it "handles free variables" do
+    allow(fake).to receive(:return_this).and_return("different")
+    expect(fake.return_this("test")).to eq("different")
+  end
+
+  it "raises on type cast error with free variables" do
+    allow(fake).to receive(:return_this).and_return(42)
+    expect { fake.return_this("test") }.to raise_error(TypeCastError, /String/)
+  end
+
+  it "handles free variables with a block" do
+    allow(fake).to receive(:map).and_return("stub")
+    expect(fake.map(:mapped, &.to_s)).to eq("stub")
+  end
+
+  it "raises on type cast error with a block and free variables" do
+    allow(fake).to receive(:map).and_return(42)
+    expect { fake.map(:mapped, &.to_s) }.to raise_error(TypeCastError, /String/)
+  end
+
+  it "handles nilable free variables" do
+    fake = mock(Test)
+    expect(fake.make_nilable("foo")).to be_nil
+  end
+end