Explicit "provided" block description

Implements https://gitlab.com/arctic-fox/spectator/-/issues/69

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]
+### Added
+- Description of a `provided` example can be set by using `it` as an argument. [#69](https://gitlab.com/arctic-fox/spectator/-/issues/69)
+
 ## [0.10.2] - 2021-10-22
 ### Fixed
 - Fix usage of `be ===` and `be =~` [#34](https://github.com/icy-arctic-fox/spectator/issues/34)

src/spectator/dsl/concise.cr

@@ -14,8 +14,9 @@ module Spectator::DSL
     # Tags and metadata cannot be used with this macro.
     #
     # ```
-    # given x = 42 do
+    # provided x = 42, y: 123 do
     #   expect(x).to eq(42)
+    #   expect(y).to eq(123)
     # end
     # ```
     macro provided(*assignments, **kwargs, &block)
@@ -26,14 +27,22 @@ module Spectator::DSL
           let({{assignment.target}}) { {{assignment.value}} }
         {% end %}
         {% for name, value in kwargs %}
-          let({{name}}) { {{value}} }
+          {% if name != :it %}let({{name}}) { {{value}} }{% end %}
         {% end %}
 
         {% if block %}
+          {% if description = kwargs[:it] %}
+            example {{description}} {{block}}
+          {% else %}
             example {{block}}
+          {% end %}
+        {% else %}
+          {% if description = kwargs[:it] %}
+            example {{description}} {{block}}
           {% else %}
             example {{assignments.splat.stringify}}
           {% end %}
+        {% end %}
       end
     end