WHILE, BREAK, and TRY/EXCEPT

Part 1 · Fundamentals›7 · Variables and control flowRFCP 5.2.5, 5.2.6

Chapter lab: Variables and control flowch07-control-flow.zip · 3 KB

This lesson continues in the same lab as the lesson before it. If you don’t have it yet, download it here.

Download ch07-control-flow.zip

Or fetch and unpack it from a terminal in VS Code:

bash / zsh

curl -fsSLO https://manykarim.github.io/robotframework-essentials-web/labs/ch07-control-flow.zip && unzip -q ch07-control-flow.zip && rm ch07-control-flow.zip

PowerShell

Invoke-WebRequest https://manykarim.github.io/robotframework-essentials-web/labs/ch07-control-flow.zip -OutFile ch07-control-flow.zip; Expand-Archive ch07-control-flow.zip -DestinationPath .; Remove-Item ch07-control-flow.zip

Open the folder in VS Code with code rfe-ch07-control-flow (or File → Open Folder…) and accept the recommended RobotCode and Python extensions. Then set it up:

uv sync

bash / zsh

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

PowerShell

python -m venv .venv
.venv\Scripts\Activate.ps1
pip install -r requirements.txt

Keep the environment active in every terminal where you run lesson commands.

poetry install --no-root

Python 3.13 or newer is required; uv installs it when it is missing.

Open in browserNo setup? Try the lab right here: its files, an editor and a terminal, running in your browser.

What's inside

• Directoryrfe-ch07-control-flow/

  • Directory.vscode/

    • extensions.json
  • Directorychecks/

    • Directorycatalog/

      • catalog.robot
    • Directorysmoke/

      • smoke.robot
  • .gitignore
  • .python-version
  • LAB.md
  • pyproject.toml
  • README.md
  • requirements.txt
  • uv.lock

Two more native structures round out control flow:

• WHILE repeats while a condition holds. BREAK exits a loop early; CONTINUE skips to the next iteration.
• TRY / EXCEPT catches a failing keyword and handles it, instead of failing the test. Optional ELSE and FINALLY blocks round it out.

Both close with END.

Task 1 — Write a WHILE loop with BREAK and a TRY/EXCEPT

Edit

Goal: create checks/robust.robot with a WHILE loop that stops early with BREAK, and a test that catches a failing keyword with TRY / EXCEPT.

Here is the same pair over different numbers and messages. Adapt them.

Worked example — adapt it, don’t copy it

*** Test Cases ***
Counts To Five
    ${n}=    Set Variable    ${0}
    WHILE    ${n} < 100
        ${n}=    Evaluate    ${n} + 1
        IF    ${n} == 5    BREAK
    END
    Should Be Equal As Integers    ${n}    5

Recovers From An Error
    TRY
        Fail    kaboom
    EXCEPT    kaboom
        Log    recovered
    END

Done when

checks/robust.robot uses WHILE and TRY, and While With Break passes.

Hint 1

Start a counter at ${0}, loop with WHILE ${i} < 10, increment inside with Evaluate, and IF ${i} == 3 BREAK. Close with END.

Hint 2

Wrap a failing keyword: TRY, then Fail boom, then EXCEPT boom, then Log handled, then END.

Solution

*** Test Cases ***
While With Break
    ${i}=    Set Variable    ${0}
    WHILE    ${i} < 10
        ${i}=    Evaluate    ${i} + 1
        IF    ${i} == 3    BREAK
    END
    Should Be Equal As Integers    ${i}    3

Try Except Handles Failure
    TRY
        Fail    boom
    EXCEPT    boom
        Log    handled
    END

Task 2 — Run the suite green

Run

Run it:

uv run robot checks

robot checks

poetry run robot checks

Done when

the test While With Break passes.

Check your understanding

Quick recall. Your first answer stays in this browser; the quiz never blocks your progress.

1. BREAK inside a loop…

   skips to the next iterationexits the loop immediatelyfails the test
   Show the answer

   Answer: exits the loop immediately — BREAK exits the loop; CONTINUE skips to the next iteration.

2. TRY/EXCEPT lets a test…

   ignore all failures silentlycatch a failing keyword and handle itretry the whole suite
   Show the answer

   Answer: catch a failing keyword and handle it — TRY/EXCEPT catches a failure from the TRY block and runs the matching EXCEPT handler instead of failing the test.

Key terms

WHILE / BREAK / CONTINUEconcept

Condition-driven loop with early exit (BREAK) and skip (CONTINUE); close with END.

TRY / EXCEPTconcept

Catch and handle a failing keyword; optional ELSE and FINALLY. Close with END.

All terms in the glossary →