diff --git a/.gitignore b/.gitignore
index d6c01c4..e5337dc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 /spec/reports/
 /tmp/
 /.rspec_status
+/spec/run/
diff --git a/spec/imbecile_spec.rb b/spec/imbecile_spec.rb
new file mode 100644
index 0000000..71b1b6b
--- /dev/null
+++ b/spec/imbecile_spec.rb
@@ -0,0 +1,35 @@
+require "fileutils"
+
+def write_grammar(grammar)
+  File.write("spec/run/test.i", grammar)
+end
+
+def build_parser
+  result = system(*%w[./imbecile.sh spec/run/test.i spec/run/test.d])
+  expect(result).to be_truthy
+end
+
+def compile
+  result = system(*%w[gdc -o spec/run/test spec/run/test.d])
+  expect(result).to be_truthy
+end
+
+describe Imbecile do
+  before(:each) do
+    FileUtils.rm_rf("spec/run")
+    FileUtils.mkdir_p("spec/run")
+  end
+
+  it "generates a D lexer" do
+    write_grammar <<EOF
+token int \\d+
+token plus \\+
+token times \\*
+drop \\s+
+rule Start [] <<
+>>
+EOF
+    build_parser
+    compile
+  end
+end