Create a new namespace for each test scenario

README.md

@@ -91,7 +91,7 @@ and in your step definition, you might have
 Resetting state between scenarios
 ---------------------------------
 
-Depending on how your test and/or application code is structured, there may be a chance of data persisting between scenarios, which could result in tests that pass or fail unexpectedly.  To eliminiate the risk of this, Cucumber TCL will start a new TCL interpreter between every scenario by creating a new instance of the 'framework' object, meaning that the env.tcl file is loaded each time.  Whilst this will remove the data leakage risk, it may also cause your scenarios to run slowly if there is a lot of setup required for a scenario to run (eg, setting up fixture data, building a database or loading large amounts of data into memory).  To override the default behaviour of starting up a new interpreter, an environment variable can be passed into the 'cucumber' command enabling the sharing of the TCL interpreter via the 'framework' object:
+Depending on how your test and/or application code is structured, there may be a chance of data persisting between scenarios, which could result in tests that pass or fail unexpectedly.  To eliminate the risk of this, Cucumber TCL will start a new TCL interpreter between every scenario by creating a new instance of the 'framework' object, meaning that the env.tcl file is loaded each time.  Whilst this will remove the data leakage risk, it may also cause your scenarios to run slowly if there is a lot of setup required for a scenario to run (eg, setting up fixture data, building a database or loading large amounts of data into memory).  To override the default behaviour of starting up a new interpreter, an environment variable can be passed into the 'cucumber' command enabling the sharing of the TCL interpreter via the 'framework' object:
 
     cucumber SHARE_FRAMEWORK=1
 

features/define_a_step.feature

@@ -98,7 +98,7 @@ Feature: Define a step
             "error "Failing Step""
                 ("eval" body line 2)
                 invoked from within
-            "eval $existing_step_body" (Tcl::Error)
+            "eval $step_body" (Tcl::Error)
             features/test.feature:3:in `Given failing'
 
       Failing Scenarios:
@@ -143,7 +143,7 @@ Feature: Define a step
             "failing_proc"
                 ("eval" body line 2)
                 invoked from within
-            "eval $existing_step_body" (Tcl::Error)
+            "eval $step_body" (Tcl::Error)
             features/test.feature:3:in `Given failing'
 
       Failing Scenarios:

features/namespace_per_test.feature

@@ -0,0 +1,51 @@
+Feature: Namespace per test
+
+  A new namespace is created for each test run, to prevent leakage of local variables between tests
+  when the option to share the TCL interpreter between tests is passed to Cucucmber
+
+  Rules:
+    -- The state is maintained between scenarios if an environment variable is passed into Cucumber
+    -- Locally defined variables are not accessible between test scenarios
+
+  Background:
+    Given a file named "features/test.feature" with:
+      """
+      Feature:
+        Scenario:
+          Given I set a global and a local variable
+          When I print the global variable
+          And I print the local variable
+
+        Scenario:
+          When I print the global variable
+          And I print the local variable
+      """
+    And a file named "features/step_definitions/steps.tcl" with:
+      """
+      global g
+      variable l
+
+      Given {^I set a global and a local variable$} {
+        set ::g value
+        set l value
+      }
+
+      When {^I print the global variable$} {
+        puts $l
+      }
+
+      When {^I print the local variable$} {
+        puts $l
+      }
+      """
+    And a file named "features/support/env.rb" with:
+      """
+      require 'cucumber/tcl'
+      """
+
+  Scenario: Local variable not persisted between tests when running 'cucumber' and sharing framework object
+    When I run `cucumber SHARE_FRAMEWORK=1`
+    Then it should fail with:
+      """
+      can't read "l": no such variable
+      """

lib/cucumber/tcl/framework.rb

@@ -18,6 +18,10 @@ def step_definition_exists?(step_name)
       def execute_step_definition(*args)
         @tcl.proc('execute_step_definition').call(*args)
       end
+
+      def next_scenario()
+        @tcl.proc('next_scenario').call()
+      end
     end
   end
 end

lib/cucumber/tcl/framework.tcl

@@ -2,6 +2,7 @@
 namespace eval ::cucumber:: {
   variable STEPS [list]
   variable TEST
+  variable SCENARIO 0
 
   # Set a variable to allow this to be more easily tested
   if {[info exists env(TEST)] && $::env(TEST) eq 1} {
@@ -11,6 +12,7 @@ namespace eval ::cucumber:: {
   }
 
   namespace export source_files
+  namespace export next_scenario
   namespace export step_definition_exists
   namespace export execute_step_definition
   namespace export Given
@@ -21,7 +23,7 @@ namespace eval ::cucumber:: {
 }
 
 #
-# Define procs to match Gherkin keyworkds that put data in the STEPS array
+# Define procs to match Gherkin keywords that put data in the STEPS array
 #
 proc ::cucumber::Given args {
   _add_step {*}$args
@@ -51,7 +53,7 @@ proc ::cucumber::_add_step args {
     error "The parameters for this procedure are regular_expression ?list_of_capture_variables? body"
     return 0
   }
-    
+
   lappend STEPS [list $re $params $body]
 }
 
@@ -72,35 +74,51 @@ proc ::cucumber::execute_step_definition { step_name {multiline_args {}} } {
 
 proc ::cucumber::_search_steps {step_name {execute 0} {multiline_args {}}} {
   variable STEPS
+  variable SCENARIO
 
   foreach step $STEPS {
     set existing_step_name   [lindex $step 0]
     set existing_step_params [lindex $step 1]
     set existing_step_body   [lindex $step 2]
 
-    if {[regexp $existing_step_name $step_name matchresult {*}[join $existing_step_params]]} {
+    if {[regexp $existing_step_name $step_name]} {
+      if {$execute == 1} {
+        set res [::cucumber::scenario_${SCENARIO}::execute_step $existing_step_name $existing_step_params $step_name $existing_step_body $multiline_args]
+        return $res
+      } else {
+        return 1
+      }
+    }
+  }
+  return 0
+}
+
+proc ::cucumber::next_scenario {} {
+  variable SCENARIO
+  incr SCENARIO
+
+  namespace eval ::cucumber::scenario_$SCENARIO {
 
+    proc execute_step {step_signature step_params step_call step_body multiline_args} {
+      regexp $step_signature $step_call matchresult {*}[join $step_params]
       # Now we've found a match, handle multiline args. The name of the var
       # should be the last value of the $existing_step_params.
       if {$multiline_args ne {}} {
-        set multiline_var_name [lindex $existing_step_params end]
+        set multiline_var_name [lindex $step_params end]
         set $multiline_var_name $multiline_args
       }
-
-      if {$execute == 1} {
-        if {[catch {
-          eval $existing_step_body
-        } msg]} {
-          if {$msg eq "pending"} {
-            return "pending"
-          }
-          error $::errorInfo
+
+      if {[catch {
+            eval $step_body
+          } msg]} {
+        if {$msg eq "pending"} {
+          return "pending"
         }
+        error $::errorInfo
       }
       return 1
     }
   }
-  return 0
 }
 
 # Sort a list of files such that: */support/env.{ext} < */support/{file} < */{file}

lib/cucumber/tcl/step_definitions.rb

@@ -7,6 +7,7 @@ module Tcl
     class StepDefinitions
       def initialize(tcl_framework)
         @tcl_framework = tcl_framework
+        @tcl_framework.next_scenario
       end
 
       def attempt_to_activate(test_step)
@@ -22,7 +23,7 @@ def match?(test_step)
 
       def action_for(test_step)
         arguments = ArgumentList.new(test_step)
-        proc { 
+        proc {
           response = ExecuteResponse.new(@tcl_framework.execute_step_definition(*arguments))
           response.raise_any_pending_error
         }