test for reinstall

Library/Homebrew/test/cmd/reinstall_spec.rb

@@ -20,4 +20,18 @@ RSpec.describe Homebrew::Cmd::Reinstall do
 
     expect(foo_dir).to exist
   end
+
+  it "reinstalls a Formula with ask input", :integration_test do
+    install_test_formula "testball"
+    foo_dir = HOMEBREW_CELLAR/"testball/0.1/bin"
+    expect(foo_dir).to exist
+    FileUtils.rm_r(foo_dir)
+
+    expect { brew "reinstall", "--ask", "testball" }
+      .to output(/.*Formula\s*\(1\):\s*testball.*/).to_stdout
+                                         .and not_to_output.to_stderr
+                                                           .and be_a_success
+
+    expect(foo_dir).to exist
+  end
 end