Coverage report formats (terminal, HTML, XML) in PyTest - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a coverage report in pytest?

A coverage report shows which parts of your code were tested and which were not during test execution.

beginner

Name three common coverage report formats supported by pytest-cov.

Terminal (text output), HTML (interactive web pages), and XML (machine-readable format).

beginner

How do you generate an HTML coverage report using pytest?

Run pytest with the option: --cov-report=html. This creates a folder named 'htmlcov' with the report files.

intermediate

What is the benefit of an XML coverage report?

XML reports can be used by other tools like CI servers to analyze coverage automatically.

beginner

What does the terminal coverage report show?

It shows a summary of coverage percentages and which lines were missed directly in the command line.

Which pytest-cov option generates an HTML coverage report?

A --cov-report=html

B --cov-report=xml

C --cov-report=term

D --cov-html

The correct option to generate an HTML report is --cov-report=html.

What folder is created by default when generating an HTML coverage report?

A coverage_report

B coverage_html

C cov_html

D htmlcov

The folder named 'htmlcov' is created by pytest-cov for HTML reports.

Which coverage report format is best for automated tools and CI servers?

A XML

B HTML

C PDF

D Terminal

XML format is machine-readable and commonly used by CI tools.

What does the terminal coverage report NOT provide?

A Summary of coverage percentages

B List of missed lines

C Interactive clickable links

D Coverage data in text form

Terminal reports are text-based and do not have interactive links.

Which command shows coverage summary directly in the terminal?

A pytest --cov-report=xml

B pytest --cov-report=term-missing

C pytest --cov-report=html

D pytest --cov-report=term

The 'term-missing' option shows coverage summary with missing lines in the terminal.

Explain the differences between terminal, HTML, and XML coverage reports in pytest.

Think about who uses each format and how.

Describe how to generate and view an HTML coverage report using pytest.

Remember the folder name and how to open the report.

Practice

1. What is the main purpose of a coverage report in pytest?

easy

A. To generate test data automatically

B. To run tests faster by skipping some tests

C. To fix bugs in the code automatically

D. To show which parts of the code were tested and which were not

Solution

1. Step 1: Understand coverage report purpose

   Coverage reports show which lines or parts of code were executed during tests.

2. Step 2: Compare options with coverage purpose

   Only To show which parts of the code were tested and which were not correctly describes this purpose; others describe unrelated actions.

3. Final Answer:

   To show which parts of the code were tested and which were not -> Option D

4. Quick Check:

   Coverage report = tested code visibility [OK]

Hint: Coverage reports show tested vs untested code [OK]

Common Mistakes:

• Confusing coverage with test execution speed
• Thinking coverage generates test data
• Believing coverage fixes bugs automatically

2. Which pytest command option generates an HTML coverage report?

easy

A. --cov-report=xml

B. --cov-report=summary

C. --cov-report=html

D. --cov-report=term

Solution

1. Step 1: Recall pytest coverage report options

   Common options include 'term' for terminal, 'html' for HTML, and 'xml' for XML reports.

2. Step 2: Match option to HTML report

   Only '--cov-report=html' generates an HTML report.

3. Final Answer:

   --cov-report=html -> Option C

4. Quick Check:

   HTML report option = --cov-report=html [OK]

Hint: HTML report uses --cov-report=html option [OK]

Common Mistakes:

• Using --cov-report=xml for HTML report
• Confusing term with html option
• Using non-existent --cov-report=summary

3. Given this pytest command:
pytest --cov=myapp --cov-report=term-missing
What will the terminal output show?

medium

A. An HTML file opened in the browser

B. A summary of coverage with missing lines shown

C. An XML file saved to disk

D. No coverage information displayed

Solution

1. Step 1: Understand --cov-report=term-missing

   This option shows coverage summary in terminal and highlights missing lines.

2. Step 2: Match output to options

   A summary of coverage with missing lines shown matches terminal summary with missing lines; others describe HTML, XML, or no output.

3. Final Answer:

   A summary of coverage with missing lines shown -> Option B

4. Quick Check:

   term-missing = terminal summary with missing lines [OK]

Hint: term-missing shows missing lines in terminal [OK]

Common Mistakes:

• Thinking term-missing opens HTML report
• Expecting XML output from term-missing
• Assuming no coverage info is shown

4. You ran pytest --cov=myapp --cov-report=html but no HTML report was generated. What is the most likely cause?

medium

A. The HTML report is saved in the current directory as 'htmlcov'

B. You forgot to install the pytest-cov plugin

C. You need to add --cov-report=xml to generate HTML

D. HTML reports are not supported by pytest

Solution

1. Step 1: Check where HTML report is saved

   By default, pytest-cov saves HTML reports in 'htmlcov' folder in current directory.

2. Step 2: Understand common confusion

   Users may think no report generated if they don't check 'htmlcov' folder; plugin installation is needed but question assumes it is installed.

3. Final Answer:

   The HTML report is saved in the current directory as 'htmlcov' -> Option A

4. Quick Check:

   HTML report folder = htmlcov [OK]

Hint: HTML report saved in 'htmlcov' folder by default [OK]

Common Mistakes:

• Assuming HTML report appears in terminal
• Forgetting to look in 'htmlcov' folder
• Thinking XML option is needed for HTML

5. You want to share coverage results with a CI tool that requires XML input. Which pytest command correctly generates the XML coverage report file?

hard

A. pytest --cov=myapp --cov-report=xml

B. pytest --cov=myapp --cov-report=html

C. pytest --cov=myapp --cov-report=term

D. pytest --cov=myapp --cov-report=term-missing

Solution

1. Step 1: Identify XML report option

   The '--cov-report=xml' option generates coverage results in XML format.

2. Step 2: Match option to CI tool requirement

   CI tools needing XML input require this exact option; others generate HTML or terminal output.

3. Final Answer:

   pytest --cov=myapp --cov-report=xml -> Option A

4. Quick Check:

   XML report option = --cov-report=xml [OK]

Hint: Use --cov-report=xml for CI XML coverage [OK]

Common Mistakes:

• Using HTML or terminal options for XML output
• Not specifying any --cov-report option
• Confusing term-missing with XML