Fix sample iteration with single block arg (not tuple)

spec/issues/github_issue_41_spec.cr

@@ -0,0 +1,30 @@
+require "../spec_helper"
+
+Spectator.describe "GitHub Issue #41" do
+  sample [1, 2, 3] do |i|
+    it "is itself" do
+      expect(i).to eq i
+    end
+  end
+
+  def self.an_array
+    [1, 2, 3]
+  end
+
+  sample an_array do |i|
+    it "is itself" do
+      expect(i).to eq(i)
+    end
+  end
+
+  # NOTE: NamedTuple does not work, must be Enumerable(T) for `sample`.
+  def self.a_hash
+    {:a => "a", :b => "b", :c => "c"}
+  end
+
+  sample a_hash do |k, v|
+    it "works on hashes" do
+      expect(v).to eq(k.to_s)
+    end
+  end
+end