add first spec for mal test cases (step2)

spec/crisp/mal_specs/mal_spec_runner.cr

@@ -0,0 +1,40 @@
+class MalTestRunner
+  def initialize(@test_file)
+  end
+
+  private macro check_EOF
+    return if l.is_a? Iterator::Stop
+  end
+
+  def each_test
+    lines = File.open(@test_file).each_line
+
+    until (l = lines.next).is_a? Iterator::Stop
+      while l =~ /^\s*(;|$)/
+        l = lines.next
+        check_EOF
+      end
+
+      check_EOF
+      input = l
+
+      output = [] of String
+      loop do
+        l = lines.next
+        check_EOF
+
+        if l =~ /^; /
+          output << l[2..-1]
+        else
+          break
+        end
+      end
+
+      if l =~ /^;=>/
+        yield input, output, l[3..-1]
+      else
+        yield input, output, nil
+      end
+    end
+  end
+end

spec/crisp/mal_specs/mal_tests_spec.cr

@@ -0,0 +1,22 @@
+require "../../helper"
+require "./mal_spec_runner.cr"
+
+describe "'Make a Lisp' tests" do
+  it "tests step2 of mal" do
+    runner = MalTestRunner.new(__DIR__ + "/tests/step2_eval.mal")
+    i = Crisp::Interpreter.new
+
+    runner.each_test do |input, output, result|
+      if result
+        r = i.print i.eval_string(input)
+      else
+        output.empty?.should be_false
+        begin
+          i.eval_string(input)
+        rescue e
+          e.message.should match(/#{output.last.chomp}/)
+        end
+      end
+    end
+  end
+end