Add pinned version to outdated json output

The structure should be consistent, so there are always pinned and
pinned_version fields even if there are no pinned versions for a given formula.

Library/Homebrew/cmd/outdated.rb

@@ -88,7 +88,9 @@ module Homebrew
 
       json << { name: f.full_name,
                 installed_versions: outdated_versions.collect(&:to_s),
-                current_version: current_version }
+                current_version: current_version,
+                pinned: f.pinned?,
+                pinned_version: f.pinned_version }
     end
     puts JSON.generate(json)
 

Library/Homebrew/test/cmd/outdated_spec.rb

@@ -38,4 +38,50 @@ describe "brew outdated", :integration_test do
         .and be_a_success
     end
   end
+
+  context "json output" do
+    it "includes pinned version in the json output" do
+      setup_test_formula "testball"
+      (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath
+
+      shutup do
+        expect { brew "pin", "testball" }.to be_a_success
+      end
+
+      expected_json = [
+        {
+          name: "testball",
+          installed_versions: ["0.0.1"],
+          current_version: "0.1",
+          pinned: true,
+          pinned_version: "0.0.1",
+        },
+      ].to_json
+
+      expect { brew "outdated", "--json=v1" }
+        .to output(expected_json + "\n").to_stdout
+        .and not_to_output.to_stderr
+        .and be_a_success
+    end
+
+    it "has no pinned version when the formula isn't pinned" do
+      setup_test_formula "testball"
+      (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath
+
+      expected_json = [
+        {
+          name: "testball",
+          installed_versions: ["0.0.1"],
+          current_version: "0.1",
+          pinned: false,
+          pinned_version: nil,
+        },
+      ].to_json
+
+      expect { brew "outdated", "--json=v1" }
+        .to output(expected_json + "\n").to_stdout
+        .and not_to_output.to_stderr
+        .and be_a_success
+    end
+  end
 end