Copy over steps.feature from wp-cli repo

Author: swissspidy

features/steps.feature

@@ -0,0 +1,59 @@
+Feature: Make sure "Given", "When", "Then" steps work as expected
+
+  Scenario: Variable names can only contain uppercase letters, digits and underscores and cannot begin with a digit.
+
+    When I run `echo value`
+    And save STDOUT as {VARIABLE_NAME}
+    And save STDOUT as {V}
+    And save STDOUT as {_VARIABLE_NAME_STARTING_WITH_UNDERSCORE}
+    And save STDOUT as {_}
+    And save STDOUT as {VARIABLE_NAME_WITH_DIGIT_2}
+    And save STDOUT as {V2}
+    And save STDOUT as {_2}
+    And save STDOUT as {2_VARIABLE_NAME_STARTING_WITH_DIGIT}
+    And save STDOUT as {2}
+    And save STDOUT as {VARIABLE_NAME_WITH_lowercase}
+    And save STDOUT as {v}
+    # Note this would give behat "undefined step" message as "save" step uses "\w+"
+    #And save STDOUT as {VARIABLE_NAME_WITH_PERCENT_%}
+
+    When I run `echo {VARIABLE_NAME}`
+    Then STDOUT should match /^value$/
+    And STDOUT should be:
+    """
+    value
+    """
+
+    When I run `echo {V}`
+    Then STDOUT should match /^value$/
+
+    When I run `echo {_VARIABLE_NAME_STARTING_WITH_UNDERSCORE}`
+    Then STDOUT should match /^value$/
+
+    When I run `echo {_}`
+    Then STDOUT should match /^value$/
+
+    When I run `echo {VARIABLE_NAME_WITH_DIGIT_2}`
+    Then STDOUT should match /^value$/
+
+    When I run `echo {V2}`
+    Then STDOUT should match /^value$/
+
+    When I run `echo {_2}`
+    Then STDOUT should match /^value$/
+
+    When I run `echo {2_VARIABLE_NAME_STARTING_WITH_DIGIT}`
+    Then STDOUT should match /^\{2_VARIABLE_NAME_STARTING_WITH_DIGIT}$/
+    And STDOUT should contain:
+    """
+    {
+    """
+
+    When I run `echo {2}`
+    Then STDOUT should match /^\{2}$/
+
+    When I run `echo {VARIABLE_NAME_WITH_lowercase}`
+    Then STDOUT should match /^\{VARIABLE_NAME_WITH_lowercase}$/
+
+    When I run `echo {v}`
+    Then STDOUT should match /^\{v}$/