diff --git a/lib/better_errors/editor.rb b/lib/better_errors/editor.rb
index 30ce6050..0e998637 100644
--- a/lib/better_errors/editor.rb
+++ b/lib/better_errors/editor.rb
@@ -56,8 +56,8 @@ def self.for_symbol(symbol)
       end
     end
 
-    # Automatically sniffs a default editor preset based on the EDITOR
-    # environment variable.
+    # Automatically sniffs a default editor preset based on
+    # environment variables.
     #
     # @return [Symbol]
     def self.default_editor
@@ -67,12 +67,15 @@ def self.default_editor
     end
 
     def self.editor_from_environment_editor
-      editor_command = ENV["EDITOR"] || ENV["BETTER_ERRORS_EDITOR"]
-      if editor_command
-        editor = editor_from_command(editor_command)
+      if ENV["BETTER_ERRORS_EDITOR"]
+        editor = editor_from_command(ENV["BETTER_ERRORS_EDITOR"])
         return editor if editor
-
-        puts "Since EDITOR or BETTER_ERRORS_EDITOR environment variable are not recognized, using Textmate by default."
+        puts "BETTER_ERRORS_EDITOR environment variable is not recognized as a supported Better Errors editor."
+      end
+      if ENV["EDITOR"]
+        editor = editor_from_command(ENV["EDITOR"])
+        return editor if editor
+        puts "EDITOR environment variable is not recognized as a supported Better Errors editor. Using TextMate by default."
       else
         puts "Since there is no EDITOR or BETTER_ERRORS_EDITOR environment variable, using Textmate by default."
       end
diff --git a/spec/better_errors/editor_spec.rb b/spec/better_errors/editor_spec.rb
new file mode 100644
index 00000000..efc73608
--- /dev/null
+++ b/spec/better_errors/editor_spec.rb
@@ -0,0 +1,233 @@
+require "spec_helper"
+
+RSpec.describe BetterErrors::Editor do
+  describe ".for_formatting_string" do
+    it "returns an object that reponds to #url" do
+      editor = described_class.for_formatting_string("custom://%{file}:%{file_unencoded}:%{line}")
+      expect(editor.url("/path&file", 42)).to eq("custom://%2Fpath%26file:/path&file:42")
+    end
+  end
+
+  describe ".for_proc" do
+    it "returns an object that responds to #url, which calls the proc" do
+      editor = described_class.for_proc(proc { |file, line| "result" } )
+      expect(editor.url("foo", 42)).to eq("result")
+    end
+  end
+
+  describe ".for_symbol" do
+    subject { described_class.for_symbol(symbol) }
+
+    [:atom].each do |symbol|
+      context "when symbol is '#{symbol}'" do
+        let(:symbol) { symbol }
+
+        it "uses atom:// scheme" do
+          expect(subject.url("file", 42)).to start_with("atom://")
+        end
+      end
+    end
+
+    [:emacs, :emacsclient].each do |symbol|
+      context "when symbol is '#{symbol}'" do
+        let(:symbol) { symbol }
+        it "uses emacs:// scheme" do
+          expect(subject.url("file", 42)).to start_with("emacs://")
+        end
+      end
+    end
+
+    [:macvim, :mvim].each do |symbol|
+      context "when symbol is '#{symbol}'" do
+        let(:symbol) { symbol }
+
+        it "uses mvim:// scheme" do
+          expect(subject.url("file", 42)).to start_with("mvim://")
+        end
+      end
+    end
+
+    [:sublime, :subl, :st].each do |symbol|
+      context "when symbol is '#{symbol}'" do
+        let(:symbol) { symbol }
+
+        it "uses subl:// scheme" do
+          expect(subject.url("file", 42)).to start_with("subl://")
+        end
+      end
+    end
+
+    [:textmate, :txmt, :tm].each do |symbol|
+      context "when symbol is '#{symbol}'" do
+        let(:symbol) { symbol }
+
+        it "uses txmt:// scheme" do
+          expect(subject.url("file", 42)).to start_with("txmt://")
+        end
+      end
+    end
+  end
+
+  describe ".default_editor" do
+    subject(:default_editor) { described_class.default_editor }
+    before do
+      ENV['BETTER_ERRORS_EDITOR_URL'] = nil
+      ENV['BETTER_ERRORS_EDITOR'] = nil
+      ENV['EDITOR'] = nil
+    end
+
+    it "returns an object that responds to #url" do
+        expect(default_editor.url("foo", 123)).to match(/foo/)
+    end
+
+    context "when $BETTER_ERRORS_EDITOR_URL is set" do
+      before do
+        ENV['BETTER_ERRORS_EDITOR_URL'] = "custom://%{file}:%{file_unencoded}:%{line}"
+      end
+
+      it "uses the value as a formatting string to build the editor URL" do
+        expect(default_editor.url("/path&file", 42)).to eq("custom://%2Fpath%26file:/path&file:42")
+      end
+    end
+
+    context "when $BETTER_ERRORS_EDITOR is set to one of the preset commands" do
+      before do
+        ENV['BETTER_ERRORS_EDITOR'] = "subl"
+      end
+
+      it "returns an object that builds URLs for the corresponding editor" do
+        expect(default_editor.url("foo", 123)).to start_with('subl://')
+      end
+    end
+
+    context "when $EDITOR is set to one of the preset commands" do
+      before do
+        ENV['EDITOR'] = "subl"
+      end
+
+      it "returns an object that builds URLs for the corresponding editor" do
+        expect(default_editor.url("foo", 123)).to start_with('subl://')
+      end
+
+      context "when $BETTER_ERRORS_EDITOR is set to one of the preset commands" do
+        before do
+          ENV['BETTER_ERRORS_EDITOR'] = "emacs"
+        end
+
+        it "returns an object that builds URLs for that editor instead" do
+          expect(default_editor.url("foo", 123)).to start_with('emacs://')
+        end
+      end
+
+      context "when $BETTER_ERRORS_EDITOR is set to an unrecognized command" do
+        before do
+          ENV['BETTER_ERRORS_EDITOR'] = "fubarcmd"
+        end
+
+        it "returns an object that builds URLs for the $EDITOR instead" do
+          expect(default_editor.url("foo", 123)).to start_with('subl://')
+        end
+      end
+    end
+
+    context "when $EDITOR is set to an unrecognized command" do
+      before do
+        ENV['EDITOR'] = "fubarcmd"
+      end
+
+      it "returns an object that builds URLs for TextMate" do
+        expect(default_editor.url("foo", 123)).to start_with('txmt://')
+      end
+    end
+
+    context "when $EDITOR and $BETTER_ERRORS_EDITOR are not set" do
+      it "returns an object that builds URLs for TextMate" do
+        expect(default_editor.url("foo", 123)).to start_with('txmt://')
+      end
+    end
+  end
+
+  describe ".editor_from_command" do
+    subject { described_class.editor_from_command(command_line) }
+
+    ["atom -w", "/usr/bin/atom -w"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses atom:// scheme" do
+          expect(subject.url("file", 42)).to start_with("atom://")
+        end
+      end
+    end
+
+    ["emacsclient", "/usr/local/bin/emacsclient"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses emacs:// scheme" do
+          expect(subject.url("file", 42)).to start_with("emacs://")
+        end
+      end
+    end
+
+    ["idea"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses idea:// scheme" do
+          expect(subject.url("file", 42)).to start_with("idea://")
+        end
+      end
+    end
+
+    ["mate -w", "/usr/bin/mate -w"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses txmt:// scheme" do
+          expect(subject.url("file", 42)).to start_with("txmt://")
+        end
+      end
+    end
+
+    ["mine"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses x-mine:// scheme" do
+          expect(subject.url("file", 42)).to start_with("x-mine://")
+        end
+      end
+    end
+
+    ["mvim -f", "/usr/local/bin/mvim -f"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses mvim:// scheme" do
+          expect(subject.url("file", 42)).to start_with("mvim://")
+        end
+      end
+    end
+
+    ["subl -w", "/Applications/Sublime Text 2.app/Contents/SharedSupport/bin/subl"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses subl:// scheme" do
+          expect(subject.url("file", 42)).to start_with("subl://")
+        end
+      end
+    end
+
+    ["vscode", "code"].each do |command|
+      context "when editor command is '#{command}'" do
+        let(:command_line) { command }
+
+        it "uses vscode:// scheme" do
+          expect(subject.url("file", 42)).to start_with("vscode://")
+        end
+      end
+    end
+  end
+end
diff --git a/spec/better_errors_spec.rb b/spec/better_errors_spec.rb
index 2ab2a486..0b5b6604 100644
--- a/spec/better_errors_spec.rb
+++ b/spec/better_errors_spec.rb
@@ -1,112 +1,49 @@
 require "spec_helper"
 
-describe BetterErrors do
-  context ".editor" do
-    it "defaults to textmate" do
-      expect(subject.editor.url("foo.rb", 123)).to eq("txmt://open?url=file://foo.rb&line=123")
-    end
-
-    it "url escapes the filename" do
-      expect(subject.editor.url("&.rb", 0)).to eq("txmt://open?url=file://%26.rb&line=0")
-    end
-
-    [:emacs, :emacsclient].each do |editor|
-      it "uses emacs:// scheme when set to #{editor.inspect}" do
-        subject.editor = editor
-        expect(subject.editor.url("file", 42)).to start_with "emacs://"
-      end
-    end
-
-    [:macvim, :mvim].each do |editor|
-      it "uses mvim:// scheme when set to #{editor.inspect}" do
-        subject.editor = editor
-        expect(subject.editor.url("file", 42)).to start_with "mvim://"
-      end
-    end
-
-    [:sublime, :subl, :st].each do |editor|
-      it "uses subl:// scheme when set to #{editor.inspect}" do
-        subject.editor = editor
-        expect(subject.editor.url("file", 42)).to start_with "subl://"
-      end
-    end
-
-    [:textmate, :txmt, :tm].each do |editor|
-      it "uses txmt:// scheme when set to #{editor.inspect}" do
-        subject.editor = editor
-        expect(subject.editor.url("file", 42)).to start_with "txmt://"
-      end
-    end
-
-    [:atom].each do |editor|
-      it "uses atom:// scheme when set to #{editor.inspect}" do
-        subject.editor = editor
-        expect(subject.editor.url("file", 42)).to start_with "atom://"
-      end
-    end
-
-    ["emacsclient", "/usr/local/bin/emacsclient"].each do |editor|
-      it "uses emacs:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "emacs://"
+RSpec.describe BetterErrors do
+  describe ".editor" do
+    context "when set to a specific value" do
+      before do
+        allow(BetterErrors::Editor).to receive(:for_symbol).and_return(:editor_from_symbol)
+        allow(BetterErrors::Editor).to receive(:for_formatting_string).and_return(:editor_from_formatting_string)
+        allow(BetterErrors::Editor).to receive(:for_proc).and_return(:editor_from_proc)
       end
-    end
 
-    ["mvim -f", "/usr/local/bin/mvim -f"].each do |editor|
-      it "uses mvim:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "mvim://"
+      context "when the value is a string" do
+        it "uses BetterErrors::Editor.for_formatting_string to set the value" do
+          subject.editor = "thing://%{file}"
+          expect(BetterErrors::Editor).to have_received(:for_formatting_string).with("thing://%{file}")
+          expect(subject.editor).to eq(:editor_from_formatting_string)
+        end
       end
-    end
 
-    ["subl -w", "/Applications/Sublime Text 2.app/Contents/SharedSupport/bin/subl"].each do |editor|
-      it "uses subl:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "subl://"
+      context "when the value is a Proc" do
+        it "uses BetterErrors::Editor.for_proc to set the value" do
+          my_proc = proc { "thing" }
+          subject.editor = my_proc
+          expect(BetterErrors::Editor).to have_received(:for_proc).with(my_proc)
+          expect(subject.editor).to eq(:editor_from_proc)
+        end
       end
-    end
 
-    ["mate -w", "/usr/bin/mate -w"].each do |editor|
-      it "uses txmt:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "txmt://"
+      context "when the value is a symbol" do
+        it "uses BetterErrors::Editor.for_symbol to set the value" do
+          subject.editor = :subl
+          expect(BetterErrors::Editor).to have_received(:for_symbol).with(:subl)
+          expect(subject.editor).to eq(:editor_from_symbol)
+        end
       end
     end
 
-
-    ["atom -w", "/usr/bin/atom -w"].each do |editor|
-      it "uses atom:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "atom://"
+    context "when no value has been set" do
+      before do
+        BetterErrors.instance_variable_set('@editor', nil)
+        allow(BetterErrors::Editor).to receive(:default_editor).and_return(:default_editor)
       end
-    end
-
-    ["mine"].each do |editor|
-      it "uses x-mine:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "x-mine://"
-      end
-    end
-
-    ["idea"].each do |editor|
-      it "uses idea:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "idea://"
-      end
-    end
 
-    ["vscode", "code"].each do |editor|
-      it "uses vscode:// scheme when EDITOR=#{editor}" do
-        ENV["EDITOR"] = editor
-        subject.editor = subject.default_editor
-        expect(subject.editor.url("file", 42)).to start_with "vscode://"
+      it "uses BetterErrors::Editor.default_editor to set the default value" do
+          expect(subject.editor).to eq(:default_editor)
+          expect(BetterErrors::Editor).to have_received(:default_editor)
       end
     end
   end