Add test

Library/Homebrew/test/formulary_spec.rb

@@ -26,6 +26,44 @@ describe Formulary do
       end
     RUBY
   end
+  let(:formula_json_contents) do
+    {
+      formula_name => {
+        "desc"                     => "testball",
+        "homepage"                 => "https://example.com",
+        "license"                  => "MIT",
+        "revision"                 => 0,
+        "version_scheme"           => 0,
+        "versions"                 => { "stable" => "0.1" },
+        "urls"                     => {
+          "stable" => {
+            "url"      => "file://#{TEST_FIXTURE_DIR}/tarballs/testball-0.1.tbz",
+            "tag"      => nil,
+            "revision" => nil,
+          },
+        },
+        "bottle"                   => {
+          "stable" => {
+            "rebuild"  => 0,
+            "root_url" => "file://#{bottle_dir}",
+            "files"    => {
+              Utils::Bottles.tag.to_s => {
+                "cellar" => ":any",
+                "url"    => "file://#{bottle_dir}/#{formula_name}",
+                "sha256" => "8f9aecd233463da6a4ea55f5f88fc5841718c013f3e2a7941350d6130f1dc149",
+              },
+            },
+          },
+        },
+        "build_dependencies"       => [],
+        "dependencies"             => [],
+        "recommended_dependencies" => [],
+        "optional_dependencies"    => [],
+        "uses_from_macos"          => [],
+        "caveats"                  => "",
+      },
+    }
+  end
   let(:bottle_dir) { Pathname.new("#{TEST_FIXTURE_DIR}/bottles") }
   let(:bottle) { bottle_dir/"testball_bottle-0.1.#{Utils::Bottles.tag}.bottle.tar.gz" }
 
@@ -201,6 +239,21 @@ describe Formulary do
         }.to raise_error(TapFormulaAmbiguityError)
       end
     end
+
+    context "when loading from the API" do
+      before do
+        allow(described_class).to receive(:loader_for).and_return(described_class::FormulaAPILoader.new(formula_name))
+        allow(Homebrew::API::Formula).to receive(:all_formulae).and_return formula_json_contents
+      end
+
+      it "returns a Formula when given a name" do
+        formula = described_class.factory(formula_name)
+        expect(formula).to be_kind_of(Formula)
+        expect {
+          formula.install
+        }.to raise_error("Cannot build from source from abstract formula.")
+      end
+    end
   end
 
   specify "::from_contents" do