Added check for svn availability

Library/Homebrew/dev-cmd/audit.rb

@@ -1228,7 +1228,9 @@ class ResourceAuditor
         end
       elsif strategy <= SubversionDownloadStrategy
         next unless DevelopmentTools.subversion_handles_most_https_certificates?
-        unless Utils.svn_remote_exists url
+        if !Utils.svn_available?
+          problem "No valid version of svn found"
+        elsif Utils.svn_remote_exists url
           problem "The URL #{url} is not a valid svn URL"
         end
       end

Library/Homebrew/test/utils/svn_spec.rb

@@ -2,37 +2,40 @@ require "utils/svn"
 
 describe Utils do
   describe "#self.svn_available?" do
-    it "returns true if svn --version command succeeds" do
-      allow_any_instance_of(Process::Status).to receive(:success?).and_return(true)
-      expect(described_class.svn_available?).to be_truthy
+    before(:each) do
+      if described_class.instance_variable_defined?(:@svn)
+        described_class.send(:remove_instance_variable, :@svn)
+      end
     end
 
-    it "returns false if svn --version command does not succeed" do
-      allow_any_instance_of(Process::Status).to receive(:success?).and_return(false)
-      expect(described_class.svn_available?).to be_falsey
-    end
-
-    it "returns svn version if already set" do
-      described_class.instance_variable_set(:@svn, true)
+    it "returns svn version if svn available" do
       expect(described_class.svn_available?).to be_truthy
     end
   end
 
   describe "#self.svn_remote_exists" do
-    let(:url) { "https://dl.bintray.com/homebrew/mirror/" }
-
     it "returns true when svn is not available" do
-      described_class.instance_variable_set(:@svn, false)
-      expect(described_class.svn_remote_exists(url)).to be_truthy
+      allow(Utils).to receive(:svn_available?).and_return(false)
+      expect(described_class.svn_remote_exists("blah")).to be_truthy
     end
 
-    it "returns false when remote does not exist" do
-      expect(described_class.svn_remote_exists(url)).to be_falsey
-    end
+    context "when svn is available" do
+      before do
+        allow(Utils).to receive(:svn_available?).and_return(true)
+      end
 
-    it "returns true when remote exists" do
-      allow_any_instance_of(Process::Status).to receive(:success?).and_return(true)
-      expect(described_class.svn_remote_exists(url)).to be_truthy
+      it "returns false when remote does not exist" do
+        expect(described_class.svn_remote_exists(HOMEBREW_CACHE/"install")).to be_falsey
+      end
+
+      it "returns true when remote exists", :needs_network do
+        remote = "http://github.com/Homebrew/install"
+        svn = HOMEBREW_SHIMS_PATH/"scm/svn"
+
+        HOMEBREW_CACHE.cd { system svn, "checkout", remote }
+
+        expect(described_class.svn_remote_exists(HOMEBREW_CACHE/"install")).to be_truthy
+      end
     end
   end
 end

Library/Homebrew/utils/svn.rb

@@ -1,6 +1,7 @@
 module Utils
   def self.svn_available?
-    @svn ||= quiet_system HOMEBREW_SHIMS_PATH/"scm/svn", "--version"
+    return @svn if instance_variable_defined?(:@svn)
+    @svn = quiet_system HOMEBREW_SHIMS_PATH/"scm/svn", "--version"
   end
 
   def self.svn_remote_exists(url)