Allow PryTester to test commands that mutate eval_string

test/helper.rb

@@ -219,19 +219,17 @@ class PryTester
     if context
       @pry.binding_stack << Pry.binding_for(context)
     end
+
+    reset_output
   end
 
   def eval(*strs)
-    @out = StringIO.new
-    @pry.output = @out
+    reset_output
     result = nil
 
     strs.flatten.each do |str|
       if @pry.process_command(str)
-        result = last_command_result
-        if result == Pry::Command::VOID_VALUE
-          result = last_output
-        end
+        result = last_command_result_or_output
       else
         result = @pry.evaluate_ruby(str)
       end
@@ -244,12 +242,31 @@ class PryTester
     @out.string if @out
   end
 
+  def process_command(command_str, eval_str = '')
+    @pry.process_command(command_str, eval_str) or raise "Not a valid command"
+    last_command_result_or_output
+  end
+
   protected
 
   def last_command_result
     result = Thread.current[:__pry_cmd_result__]
     result.retval if result
   end
+
+  def last_command_result_or_output
+    result = last_command_result
+    if result != Pry::Command::VOID_VALUE
+      result
+    else
+      last_output
+    end
+  end
+
+  def reset_output
+    @out = StringIO.new
+    @pry.output = @out
+  end
 end
 
 CommandTester = Pry::CommandSet.new do
@@ -262,6 +279,10 @@ CommandTester = Pry::CommandSet.new do
   end
 end
 
+def unindent(*args)
+  Pry::Helpers::CommandHelpers.unindent(*args)
+end
+
 # to help with tracking down bugs that cause an infinite loop in the test suite
 if ENV["SET_TRACE_FUNC"]
   require 'set_trace' if Pry::Helpers::BaseHelpers.rbx?

test/test_default_commands/test_input.rb

@@ -3,15 +3,22 @@ require 'helper'
 describe "Pry::DefaultCommands::Input" do
   before do
     @str_output = StringIO.new
+    @t = pry_tester
   end
 
   describe "amend-line" do
     it 'should correctly amend the last line of input when no line number specified ' do
-      redirect_pry_io(InputTester.new("def hello", "puts :bing", "amend-line puts :blah", "show-input", "exit-all"), @str_output) do
-        pry
-      end
+      eval_str = unindent(<<-STR)
+        def hello
+          puts :bing
+      STR
 
-      @str_output.string.should =~ /\A\d+: def hello\n\d+: puts :blah/
+      @t.process_command 'amend-line   puts :blah', eval_str
+
+      eval_str.should == unindent(<<-STR)
+        def hello
+          puts :blah
+      STR
     end
 
     it 'should correctly amend the specified line of input when line number given ' do