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Run a flow with different data

Repeat one module for every value in a list, such as each user, search term or product.

Advanced, about 10 min

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A data-driven test runs the same flow several times with different inputs. In Optics, you write the flow once as a module, keep the inputs in a list, and use Run Loop to run the module once per item.

Run Loop sets term to each value in the list in turn, and runs the module once per value.

Loop over a list of values#

This example signs in to the Sauce Labs demo store as three different users, signing out after each one. It runs as written with the Playwright setup from Write your first test.

test_data/elements.csv
Element_Name,Element_ID
username_field,//input[@id='user-name']
password_field,//input[@id='password']
login_button,//input[@id='login-button']
menu_button,//button[@id='react-burger-menu-btn']
logout_link,//a[@id='logout_sidebar_link']
shoppers,standard_user|visual_user|problem_user
username,placeholder
modules/modules.csv
module_name,module_step,param_1,param_2,param_3
Open the store,Launch App,https://www.saucedemo.com
Sign In Each Shopper,Run Loop,Sign In And Out,username,${shoppers}
Sign In And Out,Enter Text,${username_field},${username}
Sign In And Out,Enter Text,${password_field},secret_sauce
Sign In And Out,Press Element,${login_button}
Sign In And Out,Assert Presence,Products
Sign In And Out,Press Element,${menu_button}
Sign In And Out,Sleep,1
Sign In And Out,Press Element,${logout_link}
Sign In And Out,Assert Presence,${login_button}
test_cases/test_cases.csv
test_case,test_step
Suite Setup,Open the store
Every shopper can sign in,Sign In Each Shopper

Run Loop,Sign In And Out,username,${shoppers} reads: *run the module Sign In And Out once for each value in shoppers, and set username to that value each time.* Inside the module, ${username} is the current shopper.

A few details make this work:

  • **username is written without ${}** in the Run Loop step, because the loop writes it. See Variables.
  • **username,placeholder** in the elements file lets optics dry_run accept ${username}. The loop replaces it.
  • **The values are separated by |.** You can also write them straight into the step: Run Loop,Sign In And Out,username,standard_user|visual_user.
  • **Sleep,1** waits for the menu to slide open. Prefer a check such as Assert Presence to wait for a new screen, but use a short sleep for an animation on an element that's already on the page.

The run shows the loop as one step. If any pass fails, the loop stops and the step fails with the reason:

└── Every shopper can sign in                                     |  5.86s |    PASS
    └── Sign In Each Shopper                                      |  5.86s |    PASS
        └── Run Loop (Sign In And Out, username, standard_user… |  5.86s |    PASS

Loop over several lists at once#

Give more name and list pairs to set several variables per pass. The lists are read side by side, and the loop stops at the end of the shortest:

modules/modules.csv
module_name,module_step,param_1,param_2,param_3,param_4,param_5
Every Search,Run Loop,Search And Check,term,trail|pace|ridge,expected,Trail Runner 2|Pace Knit|Ridge GTX
Search And Check,Press Element,${search_bar}
Search And Check,Enter Text Direct,${term}
Search And Check,Assert Presence,${expected}

Each pass sets term and expected from the same position in their lists: first trail and Trail Runner 2, then pace and Pace Knit, and so on. Add term,placeholder and expected,placeholder to your elements file for dry runs.

Repeat a module a number of times#

Give a count instead of lists:

modules/modules.csv
module_name,module_step,param_1,param_2
Fill Cart,Run Loop,Add One Item,3

Keep the data in a file#

Lists can live in an elements file, as shoppers does above, or as a JSON list: sizes,"[""8"",""9"",""10""]". For a single value from a larger data file, such as the email address of the admin user, use Read Data:

test_data/users.csv
username,email,role
ava,[email protected],admin
ben,[email protected],shopper
modules/modules.csv
module_name,module_step,param_1,param_2,param_3
Sign In As Admin,Read Data,admin_email,test_data/users.csv,role == 'admin';select=email
Sign In As Admin,Enter Text,${email_field},${admin_email}

The query picks rows with a filter (role == 'admin') and columns with select=. Compare values as quoted text, because every value in the file is read as text. Read Data is designed to fetch one row; with several matching rows, the variable gets a combined value that's hard to use.

Rules inside a loop#

Steps inside a looped module run a little differently from top-level steps:

  • Only the first value of each element is used. Fallbacks don't apply, so give looped elements a reliable first value.
  • **name=value parameters aren't available.** Pass values in order instead.
  • The module's steps don't appear separately in the run tree or the JUnit report. A failure names the step that failed in its message.
  • After the loop, the variable keeps its last value.

See also#