Add Resolver::DependencyRequest#match?

This new method only matches prerelease versions when this is a
prerelease dependency.

Part of #853

lib/rubygems/resolver/dependency_request.rb

@@ -42,7 +42,19 @@ def development?
   end
 
   ##
-  # Does this dependency request match +spec+
+  # Does this dependency request match +spec+?
+  #
+  # NOTE:  #match? only matches prerelease versions when #dependency is a
+  # prerelease dependency.
+
+  def match? spec
+    @dependency.match? spec
+  end
+
+  ##
+  # Does this dependency request match +spec+?
+  #
+  # NOTE:  #matches_spec? matches prerelease versions.  See also #match?
 
   def matches_spec?(spec)
     @dependency.matches_spec? spec

test/rubygems/test_gem_resolver_dependency_request.rb

@@ -22,6 +22,29 @@ def test_development_eh
     assert b_dep_req.development?
   end
 
+  def test_match_eh
+    spec = util_spec 'a', 1
+    dependency = dep 'a', '>= 1'
+
+    dr = @DR.new dependency, nil
+
+    assert dr.match? spec
+  end
+
+  def test_match_eh_prerelease
+    spec = util_spec 'a', '1.a'
+
+    a_dep = dep 'a', '>= 1'
+    a_dr = @DR.new a_dep, nil
+
+    refute a_dr.match? spec
+
+    a_pre_dep = dep 'a', '>= 1.a'
+    a_pre_dr = @DR.new a_pre_dep, nil
+
+    assert a_pre_dr.match? spec
+  end
+
   def test_requirement
     dependency = dep 'a', '>= 1'