Category: behave

Behave – Step Parameters ”; Previous Next We can have parameters within the step names. These parameters can be taken care of by the regular expressions or by the default or extended parser with the help of the use_step_matcher method. behave.use_step_matcher(name) Modify the parameter matcher in parsing the step text. There are multiple in-built parsers present in Behave, as explained below − parse − It gives an easy parser that restores regular expression for the step parameters with plain syntax. For example, {parameter: type}. It allows type conversion with type converters. cfparse − It has the Cardinality Field (CF) support. By default, it generates the missing type converters for connected cardinality (if type converter for cardinality equal to one is given). It can support the below parse expressions − {values:Type+} – Cardinality=1..N, many {values:Type*} – Cardinality=0..N, many0 {values:Type?} – Cardinality=0..1, optional It allows type conversion with type converters. re − It utilises the complete regular expressions to parse the clause. We have to take the help of the named groups (? P<name>…) to declare variables obtained from the text and then feed it to the step (). We can have our customised matcher along with new data types with the help of the register_type method. behave.register_type(w) Registers a user defined type for parsing during type conversion at the time of step matching. class behave.matchers.Matcher(func, pattern ,step_type=None) It extracts the parameters out of step names. pattern − The pattern matching associated with the step function. func − The step function is the pattern is associated with. check_match(step) − To match with the step name provided. describe(schema=None) − Give description in form of text of the function or matcher object. regex_pattern: Yields the utilised textual regex expression. class behave.model_core.Argument(start, end, original, value, name=Name) An argument for a step name in the feature file obtained with step decorator parameters. The attributes are as follows − original − The original text which is matched in the name of the step. value − The value of the argument which is type converted. name − The argument name. The value is set to None, if the parameter is not given. start − The starting index of the argument in step name. end − The ending index of the argument in step name. class behave.matchers.Match(func, arguments=None) A step in the feature file which is parameter-matched and obtained with step decorator parameters. The attributes are as follows − func − The step function which is applicable to the given match. arguments − The argument list the instances having the matched parameter obtained from the name of the step. Print Page Previous Next Advertisements ”;

Behave – Optional Part ”; Previous Next There are maybe steps in the feature file having almost similar phrases. Behave has the parsing ability so that one step definition can cover these steps. The method use_step_parser is used for this and we have to pass the parser type as a parameter to that method. For extended parse matchers, we have to pass the parameter cfparse. It has the Cardinality Field (CF) support. By default, it generates the missing type converters for connected cardinality (if type converter for cardinality equal to one is given). It can support the below parse expressions − {values:Type+} – Cardinality=1..N, many {values:Type*} – Cardinality=0..N, many0 {values:Type?} – Cardinality=0..1, optional Feature File (almost similar steps) The feature file with almost similar steps is as follows − Feature − Payment Process Scenario − Check Debit transactions Given user is on “debit” screen Scenario − Check Credit transactions Given user is on “credit” screen The method register_type is used to register a user defined type that can be parsed for any type conversion at the time of matching the step. Corresponding Step Implementation File The step implementation file is given below − from behave import * import parse #define parse type use_step_matcher(“cfparse”) # for whitespace characters @parse.with_pattern(r”xs+”) def parse_string(s): #type converter for “x” succeeded by single/multiple spaces return s.strip() #register user-defined datatype register_type(x_=parse_string) #optional part :x_? cardinality field in parse expression @given(”user is on {:x_?}{payment} screen”) def step_payment(context, x_, payment): print(“Payment type: “) print(payment) Output The output obtained after running the feature file is given below and the command used is behave –no-capture -f plain. The output shows the debit and credit. These two values have been passed with almost similar steps in the feature file. In step implementation, we have parsed both the steps with cardinality fields within parse expression. Print Page Previous Next Advertisements ”;

Behave – Step Functions ”; Previous Next Step functions are created in the Python files which exist within the steps directory. Every Python file (having extension as .py) inside that directory gets imported to get the step implementations. Once the feature files get triggered for execution, the implementation files get loaded. The step functions are associated with the step decorators. The step implementations must begin with the import, by using the command mentioned below − from behave import * This will import multiple decorators described in Behave to help us to locate our step functions. The decorators like the given, when, then, and so on accepts one string argument. For example, consider the code given herewith − @given(”user is on admin screen”) def step_impl(context): pass The above code shall match the Given step of the below feature file, which is as follows − Feature − Admin Module Scenario − Admin verification Given user is on admin screen The steps starting with And/But in the feature file are renamed to their earlier step keyword. For example, consider the feature file given below − Feature − Admin Module Scenario − Admin verification Given user is on admin screen And user is on history screen Then user should be able to see admin name But user should not able to check history The And step shall be renamed to the Given step and the But step shall be renamed to the earlier step keyword. All these are handled internally. If there are more than one And/But steps consecutively, they would inherit the keyword of non And or But keyword. The step function having the step decorator shall have a minimum one parameter. The first parameter is known as the context variable. Other parameters come from step parameters (if required). For example, refer the step function as per the step parameter. @given(”user is on admin screen”) def step_impl(context): pass Project Structure The project structure for the feature is as follows − Print Page Previous Next Advertisements ”;

Behave – Enumeration ”; Previous Next Enumeration is used to map the multiple distinctive string based words to the values. We may require a user-defined data type having the following characteristics − A handful of words must be matched. Pre-defined values prior to the test execution. For the above scenarios, enumeration based on string can be used. Feature File Consider a feature file for the Feature titled payment process, as mentioned below − Feature − Payment Process Scenario − Response When User asks “Is payment done?” Then response is “No” In the step implementation file, TypeBuilder.make_enum function evaluates a regular expression pattern for the provided enumeration of words or strings. The method register_type is used to register a user defined type that can be parsed for any type conversion at the time of matching the step. Also, we shall pass the parameter: user-defined enum datatype enclosed in “{}”. Corresponding Step Implementation File The step implementation file for the above Feature is as follows − from behave import * from behave import register_type from parse_type import TypeBuilder # — ENUM: Yields True (for “yes”), False (for “no”) parse_response = TypeBuilder.make_enum({“yes”: True, “no”: False}) register_type(Response=parse_response) @when(”User asks “{q}””) def step_question(context, q): print(“Question is: “) print(q) @then(”response is “{a:Response}””) def step_answer(context, a): print(“Answer is: “) print(a) Output The output obtained after running the feature file is mentioned below. Here, we have used the command behave –no-capture -f plain. The output shows Is payment done? and False. The output False comes from the enumeration data type. Print Page Previous Next Advertisements ”;

Behave – Steps in a Step ”; Previous Next We can substitute multiple steps in a Scenario with one macro step. This helps us not to repeat the same code in the step definition file. A BDD framework has the capability to invoke multiple steps from the step definition. Feature File with Similar Steps The feature file with the similar steps is as follows − Feature − Payment Module Scenario − Verify message after payment Given User is on payment screen When User enters payment details And User completes payment Then User should get success message Scenario − Verify new users can process payment Given User keys in payment info and submits Then success message should get displayed In the feature file, we have two Scenario with similar steps. In Behave, we can execute more than one step in a single step. This can be done with the help of context.execute_steps method in the step implementation file. Corresponding Step Implementation File The corresponding step implementation file for the above mentioned feature file is as follows − from behave import * @given(”User is on payment screen”) def is_on_payment_screen(context): print(”User is on payment screen”) @when(”User enters payment details”) def enters_payment_details(context): print(”When User enters payment details”) @when(”User completes payment”) def completes_payment(context): print(”When User completes payment”) @then(”User should get success message”) def get_success_message(context): print(”Then User should get success message”) @given(”User keys in payment info and submits”) def payment_info_and_submits(context): #passing steps within steps with context.execute_steps context.execute_steps(u””” Given User is on payment screen When User enters payment details And User completes payment “””) @then(”success message should get displayed”) def success_message(context): print(”Then success message should get displayed”) Output The output obtained after running the feature file is given below and the command used is behave –no-capture -f plain. The continued output is as follows − The output shows that the new users of Scenario Verify can process the payment by having the steps executed from the Scenario Verify new users can process payment. Print Page Previous Next Advertisements ”;

Behave – Scenario Outlines ”; Previous Next A Scenario Outline is used if we have a group of similar criteria and the results are to be passed in a Scenario. A Scenario Outline is accompanied with an Examples table. A Scenario Outline can have multiple Examples tables. The tests get executed once for every row found (after the header row) within the Examples table. The values to be tested are represented by their names enclosed in brackets<>. These names should match with the Examples table header. It helps to reduce the lines of code (eliminates repeating steps) and orders our tests. Feature File The feature file for scenario outline is as follows − Feature − User information Scenario Outline: Check login functionality Given user enters “<name>” and “<password>” Then user should be logged in Examples: Credentials | name | password | | user1 | pwd1 | | user2 | pwd2 | Please Note: We have kept the name and password parameters enclosed in “<>”. These parameters are column headers provided below the Examples section. In the step implementation, we shall pass the parameters enclosed in “{}”. Also, these parameters need to be passed as arguments to the implementation method. Corresponding Step Implementation File The corresponding step implementation file is as follows − from behave import * @given(”user enters “{name}” and “{password}””) def step_implpy(context, name, password): print(“Username for login: {}”.format(name)) print(“Password for login: {}”.format(password)) @then(”user should be logged in”) def step_implpy(context): pass Output The output is obtained after running the feature file and the command used is behave –no-capture -f plain. The output shows Username for login: user1, Password for login: pwd1 and Username for login: user2, Password for login: pwd2 printed. Here, the two data sets were passed from the Examples. Print Page Previous Next Advertisements ”;

Behave – Setup Table ”; Previous Next A step can have a text and data table associated with it. We can add a data table with a step. It is recommended to have the table data indented and it is mandatory to have an equal column number for each line. A column data should be separated by the | symbol. Feature File with Table (Login.feature) The feature file is as mentioned below − Feature − User Information Scenario − Check login functionality Given Collection of credentials | username |password | | user1 | pwd1 | | user2 | pwd2 | Then user should be logged in A table is accessible to the implementation Python code with the .table attribute within the context variable (passed in the step function). A table is an instance of Table. We can use the set up table to facilitate setting up the test. Python code The python code to access table.(login_module.py) is as follows − class Deprt(object): def __init__(self, username, ms=None): if not ms: ms = [] self.username = username self.ms = ms def m_addition(self, usernane): assert usernane not in self.ms self.ms.append(usernane) class LModel(object): def __init__(self): self.loginusrs = []f self.passwords = {} def usr_addition(self, username, password): assert username not in self.loginusrs if password not in self.passwords: self.passwords[password] = Deprt(password) self.passwords[password].m_addition(username) Corresponding Step Implementation File(step_implg.py) The file is as follows − from behave import * from features.steps.login_module import LModel @given(”Collection of credentials”) def step_impl(context): model = getattr(context, “model”, None) if not model: context.model = LModel() #iterate rows of table for r in context.table: context.model.usr_addition(r[“username”], password=r[“password”]) @then(”user should be logged in”) def step_impl(context): pass Project setup The project set up for the file in Python project is as follows Output The output obtained after running the feature file is given below and the command used is behave –no-capture -f plain. The output shows the step up table printed. Print Page Previous Next Advertisements ”;

Behave – Background ”; Previous Next A Background is added to have a group of steps. It is close to a Scenario. We can add a context to multiple Scenarios with Background. It is run prior to every Scenario of a feature, but post the execution of before hooks. Background is generally used for executing preconditions like login Scenarios or database connection, and so on. A Background description can be added for the better human readability. It can appear only for a single time in a feature file and must be declared prior to a Scenario or Scenario Outline. A Background should not be used to create a complex state (only if it cannot be avoided). This segment should be brief and authentic. Also, we should avoid having a large number of scenarios within one feature file. Feature File with Background The feature file with background for the feature titled payment process is as follows − Feature − Payment Process Background: Given launch application Then Input credentials Scenario − Credit card transaction Given user is on credit card payment screen Then user should be able to complete credit card payment Scenario − Debit card transaction Given user is on debit card payment screen Then user should be able to complete debit card payment Corresponding Step Implementation File The file is given below − from behave import * @given(”launch application”) def launch_application(context): print(”launch application”) @then(”Input credentials”) def input_credentials(context): print(”Input credentials”) @given(”user is on credit card payment screen”) def credit_card_pay(context): print(”User is on credit card payment screen”) @then(”user should be able to complete credit card payment”) def credit_card_pay_comp(context): print(”user should be able to complete credit card pay”) @given(”user is on debit card payment screen”) def debit_card_pay(context): print(”User is on debit card payment screen”) @then(”user should be able to complete debit card payment”) def debit_card_pay_comp(context): print(”user should be able to complete debit card payment”) Output The output obtained after running the feature file is mentioned below and the command used here is behave –no-capture -f plain. The continued output is as follows − The output shows the Background steps (Given Launch applications & Then Input Credentials) running twice before each of the Scenarios. Print Page Previous Next Advertisements ”;

Behave – Supported Languages ”; Previous Next We have the option to utilise other languages apart from English in the feature file. This is because, the majority of BDD tools have the support for internationalisation. The important fact is that the keywords – Then, When, Given can be described in other native languages like Spanish, French, and so on. In that case, the developer can implement the step definitions in other languages as well. The list of all the languages can be obtained with the command: behave –lang-list. The following screen will appear on your computer after using the command behave –lang-list − Some more languages included in Behave are mentioned below − A feature file can be associated with a particular language. At this time, the BDD framework chooses the keywords for that specific language. The language can be set as default in the configuration file. Behave configuration files can be either, .behaverc or behave.ini files. The value for the parameter lang should be set to da in the configuration file, if we want the language to be to Danish. Configuration file setup The feature file set up for selecting a particular language is given below and the language used as an example is Danish (da). [behave] lang = da Print Page Previous Next Advertisements ”;

Behave – Step Matchers ”; Previous Next There are three types of Step Matchers in Behave. They are explained below − ParseMatcher (parse) − Based on the parse module. extended ParseMatcher(cfparse) − Allows cardinality syntax. RegexMatcher (re) − Based on regular expressions for matching patterns. Parse matcher It is the in-built step matcher which has the below mentioned features: Simple to use and comprehend. Predefined and user-defined data types support this matcher. Re-utilises regular expressions with the help of data types. Conceals the complexity of regular expression. extended Parse matcher It extends the Parse Matcher. It has additional features along with the features of Parse matcher. The additional features include − Comprehends the cardinality field syntax. Generates missing type converters for the fields with cardinality field parts. Built on parse-type. Regex matcher It has the below features − Backward compatible to Cucumber. Easier to use compared to a parse matcher. Let us understand the parse matchers in detail. Parse Matchers There are maybe steps in the feature file having almost similar phrases. Behave has the parsing ability. The method use_step_parser is used for this and we have to pass the parser type as a parameter to that method. For parse matchers, we have to pass the parameter parse. It utilises the parse for regular expressions parsing and matching. Feature File (almost Given similar steps) The feature file for the similar steps is as follows − Feature − Payment Process Scenario − Check Debit transactions Given user is on “debit” screen When user makes a payment Scenario − Check Credit transactions Given user is on “credit” screen Corresponding Step Implementation File The step implementation file is as follows − from behave import * #define parser type use_step_matcher(“parse”) @given(”user is on “{p}” screen”) def step_impl(context, p): print(p) @when(”user makes a payment”) def step_pay_complete(context): pass Output The output obtained after running the feature file is mentioned below. Here, we have used the command behave –no-capture -f plain. The output shows debit and credit. These two values have been passed with almost similar Given steps in the feature file. In step implementation, we have parsed both the steps. Print Page Previous Next Advertisements ”;