Allow for regular expression filters

Fixes simplecov-ruby#514

lib/simplecov/configuration.rb

@@ -293,12 +293,10 @@ def add_group(group_name, filter_argument = nil, &filter_proc)
     def parse_filter(filter_argument = nil, &filter_proc)
       if filter_argument.is_a?(SimpleCov::Filter)
         filter_argument
-      elsif filter_argument.is_a?(String)
-        SimpleCov::StringFilter.new(filter_argument)
       elsif filter_proc
         SimpleCov::BlockFilter.new(filter_proc)
-      elsif filter_argument.is_a?(Array)
-        SimpleCov::ArrayFilter.new(filter_argument)
+      elsif filter_argument
+        SimpleCov::Filter.class_for_argument(filter_argument).new(filter_argument)
       else
         raise ArgumentError, "Please specify either a string or a block to filter with"
       end

lib/simplecov/defaults.rb

@@ -25,8 +25,8 @@
 SimpleCov.profiles.define "rails" do
   load_profile "test_frameworks"
 
-  add_filter "/config/"
-  add_filter "/db/"
+  add_filter %r{^/config/}
+  add_filter %r{/^/db/}
 
   add_group "Controllers", "app/controllers"
   add_group "Channels", "app/channels" if defined?(ActionCable)

lib/simplecov/filter.rb

@@ -24,6 +24,18 @@ def passes?(source_file)
       warn "#{Kernel.caller.first}: [DEPRECATION] #passes? is deprecated. Use #matches? instead."
       matches?(source_file)
     end
+
+    def self.class_for_argument(filter_argument)
+      if filter_argument.is_a?(String)
+        SimpleCov::StringFilter
+      elsif filter_argument.is_a?(Regexp)
+        SimpleCov::RegexFilter
+      elsif filter_argument.is_a?(Array)
+        SimpleCov::ArrayFilter
+      else
+        raise ArgumentError, "You have provided an unrecognized filter type"
+      end
+    end
   end
 
   class StringFilter < SimpleCov::Filter
@@ -34,6 +46,14 @@ def matches?(source_file)
     end
   end
 
+  class RegexFilter < SimpleCov::Filter
+    # Returns true when the given source file's filename matches the
+    # regex configured when initializing this Filter with RegexFilter.new(/someregex/)
+    def matches?(source_file)
+      (source_file.project_filename =~ filter_argument)
+    end
+  end
+
   class BlockFilter < SimpleCov::Filter
     # Returns true if the block given when initializing this filter with BlockFilter.new {|src_file| ... }
     # returns true for the given source file.

lib/simplecov/source_file.rb

@@ -80,6 +80,12 @@ def initialize(filename, coverage)
       @coverage = coverage
     end
 
+    # The path to this source file relative to the projects directory
+    def project_filename
+      project_dir = File.dirname(File.expand_path(File.basename(__FILE__)))
+      @filename.sub(/^#{project_dir}/, "")
+    end
+
     # The source code for this file. Aliased as :source
     def src
       # We intentionally read source code lazily to

spec/filters_spec.rb

@@ -26,6 +26,22 @@
       expect(SimpleCov::StringFilter.new("sample.rb")).to be_matches subject
     end
 
+    it "matches a new SimpleCov::StringFilter '/fixtures/'" do
+      expect(SimpleCov::StringFilter.new("sample.rb")).to be_matches subject
+    end
+
+    it "matches a new SimpleCov::RegexFilter /\/fixtures\//" do
+      expect(SimpleCov::RegexFilter.new(/\/fixtures\//)).to be_matches subject
+    end
+
+    it "doesn't match a new SimpleCov::RegexFilter /^\/fixtures\//" do
+      expect(SimpleCov::RegexFilter.new(/^\/fixtures\//)).not_to be_matches subject
+    end
+
+    it "matches a new SimpleCov::RegexFilter /^\/spec\//" do
+      expect(SimpleCov::RegexFilter.new(/^\/spec\//)).to be_matches subject
+    end
+
     it "doesn't match a new SimpleCov::BlockFilter that is not applicable" do
       expect(SimpleCov::BlockFilter.new(proc { |s| File.basename(s.filename) == "foo.rb" })).not_to be_matches subject
     end
@@ -94,5 +110,19 @@
         expect(SimpleCov.filtered(subject)).to be_a SimpleCov::FileList
       end
     end
+
+    describe ".class_for_argument" do
+      it "returns SimpleCov::StringFilter for a string" do
+        expect(SimpleCov::Filter.class_for_argument("filestring")).to eq(SimpleCov::StringFilter)
+      end
+
+      it "returns SimpleCov::RegexFilter for a string" do
+        expect(SimpleCov::Filter.class_for_argument(/regex/)).to eq(SimpleCov::RegexFilter)
+      end
+
+      it "returns SimpleCov::RegexFilter for a string" do
+        expect(SimpleCov::Filter.class_for_argument(%w[file1 file2])).to eq(SimpleCov::ArrayFilter)
+      end
+    end
   end
 end

spec/source_file_spec.rb

@@ -16,6 +16,10 @@
         expect(subject.src).to eq(subject.source)
       end
 
+      it "has a project filename which removes the project directory" do
+        expect(subject.project_filename).to eq("/spec/fixtures/sample.rb")
+      end
+
       it "has source_lines equal to lines" do
         expect(subject.lines).to eq(subject.source_lines)
       end