Fix sample iteration with single block arg (not tuple)

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+###
+- Fixed usage of `sample` with single block argument. [#41](https://github.com/icy-arctic-fox/spectator/issues/41#issuecomment-1022525702)
+
 ## [0.10.4] - 2022-01-11
 ### Added
 - Support string interpolation for example name/description. [#41](https://github.com/icy-arctic-fox/spectator/issues/41)

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

src/spectator/dsl/groups.cr

@@ -101,9 +101,15 @@ module Spectator::DSL
           )
 
           \{% if block %}
-            \{% for arg, i in block.args %}
-              let(\{{arg}}) do |example|
-                example.group.as(::Spectator::ExampleGroupIteration(typeof(Group\%group.\%collection.first))).item[\{{i}}]
+            \{% if block.args.size > 1 %}
+              \{% for arg, i in block.args %}
+                let(\{{arg}}) do |example|
+                  example.group.as(::Spectator::ExampleGroupIteration(typeof(Group\%group.\%collection.first))).item[\{{i}}]
+                end
+              \{% end %}
+            \{% else %}
+              let(\{{block.args[0]}}) do |example|
+                example.group.as(::Spectator::ExampleGroupIteration(typeof(Group\%group.\%collection.first))).item
               end
             \{% end %}