Coverage report formats (terminal, HTML, XML) in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pytest coverage terminal report

What is the output of the following pytest coverage command when run in a terminal?

pytest --cov=my_module --cov-report=term

A An XML file named coverage.xml is created in the current directory.

B An HTML file named index.html is generated in a directory named htmlcov.

C A summary table printed in the terminal showing coverage percentages per file and total coverage.

D No output is shown; coverage data is only saved internally.

💡 Hint

Think about what the 'term' option means for coverage reports.

The 'term' coverage report option prints a coverage summary directly in the terminal after tests run.

❓ Predict Output

intermediate

Result of pytest coverage HTML report generation

After running the command below, what will you find in your project directory?

pytest --cov=my_module --cov-report=html

A A coverage.xml file with coverage data in XML format.

B No files or directories are created; output is only shown in terminal.

C A coverage.txt file with plain text coverage summary.

D A directory named htmlcov containing an index.html file and other files for viewing coverage in a browser.

💡 Hint

HTML reports are meant to be viewed in a web browser.

The 'html' report option creates a folder named htmlcov with an index.html file and related assets for a detailed coverage report.

❓ Predict Output

advanced

Effect of pytest coverage XML report option

What is the effect of running this command?

pytest --cov=my_module --cov-report=xml

A Creates an htmlcov directory with HTML coverage report files.

B Generates a coverage.xml file in the current directory containing coverage data in XML format.

C Does not generate any coverage report files.

D Prints coverage summary in the terminal only.

💡 Hint

XML reports are used for integration with other tools.

The 'xml' report option creates a coverage.xml file with coverage data in XML format for tools like CI servers.

🧠 Conceptual

advanced

Choosing coverage report formats for different needs

Which coverage report format is best suited for viewing detailed coverage information interactively in a web browser?

A HTML report format

B Terminal report format

C XML report format

D No report format

💡 Hint

Think about which format uses web pages.

HTML reports provide detailed, interactive coverage views in a browser, unlike terminal or XML formats.

❓ framework

expert

Combining multiple coverage report formats in pytest

Which command correctly generates both terminal and XML coverage reports in one pytest run?

A pytest --cov=my_module --cov-report=term,xml

B pytest --cov=my_module --cov-report=term --cov-report=xml

C pytest --cov=my_module --cov-report=term xml

D pytest --cov=my_module --cov-report=term+xml

💡 Hint

Multiple reports are separated by commas without spaces.

To generate multiple coverage reports, list them separated by commas with no spaces after --cov-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