Efficient Test Reporting Strategies with testthatReporter in R - GeeksforGeeks (2024)

Testing is crucial in software development to ensure code quality and functionality. In R, the testthat package is widely used for writing unit tests. One of the key features of testthat is its flexible reporting system, which helps to understand the results of our tests. Here, we’ll explore efficient test reporting strategies using testthatReporter in R.

What is testthatReporter?

testthatReporter is an object in the testthat package responsible for managing how test results are reported. There are several types of reporters available, each provides different needs such as –

• Summary Reporter: Provides a concise summary of the test results.
• Minimal Reporter: Displays minimal output, ideal for continuous integration (CI) systems.
• Progress Reporter: Shows the progress of tests, useful for interactive use.
• List Reporter: Lists all test results, including detailed information on failures and errors.
• Check Reporter: Mimics the output of R CMD check, useful for package developers.

Now we will discuss step by step implementation of Test Reporting Strategies with testthatReporter in R Programming Language.

Step 1: Installing testthat

First we will install testthat package.

install.packages("testthat")library(testthat)

Step 2: Writing Tests with testthat

Create a file named test_example.R in your project’s directory.

library(testthat)add <- function(x, y) { return(x + y)}test_that("addition works correctly", { expect_equal(add(1, 1), 2) expect_equal(add(-1, 1), 0)})

Output:

Test passed ?

Step 3: Using Different Reporters

Now we will use Different Reporters and explain one by one.

1. Summary Reporter

The Summary Reporter gives a brief overview of the test results.

# Define the path to the test directorytest_dir_path <- "E:/R lang/tests/testthat"# Use Summary Reportercat("Using Summary Reporter:\n")testthat::test_dir(test_dir_path, reporter = testthat::SummaryReporter$new())

Output:

Using Summary Reporter:
example: ..
══ DONE ════════════════════════════════════════════════════════════════════════

2. Minimal Reporter

The Minimal Reporter is useful for CI systems where you want minimal output.

# Use Minimal Reportercat("\nUsing Minimal Reporter:\n")testthat::test_dir(test_dir_path, reporter = testthat::MinimalReporter$new())

Output:

Using Minimal Reporter:
..

3. Progress Reporter

The Progress Reporter shows the progress of your tests, which is helpful for interactive use.

# Use Progress Reportercat("\nUsing Progress Reporter:\n")testthat::test_dir(test_dir_path, reporter = testthat::ProgressReporter$new())

Output:

Using Progress Reporter:
✔ | F W S OK | Context
⠏ | 0 | example 
✔ | 2 | example
══ Results ═════════════════════════════════════════════════════════════════════
[ FAIL 0 | WARN 0 | SKIP 0 | PASS 2 ]
?

4. Check Reporter

The Check Reporter mimics the output of R CMD check, which is useful for package developers.

# Use Check Reportercat("\nUsing Check Reporter:\n")testthat::test_dir(test_dir_path, reporter = testthat::CheckReporter$new())

Output:

Using Check Reporter:
[ FAIL 0 | WARN 0 | SKIP 0 | PASS 2 ]

5. Custom Reporters

If the built-in reporters do not meet our needs, we can create a custom reporter by extending the Reporter class.

# Custom ReporterCustomReporter <- R6::R6Class("CustomReporter", inherit = testthat::Reporter, public = list( start_reporter = function() { cat("Starting tests...\n") }, end_reporter = function() { cat("All tests completed.\n") }, add_result = function(context, test, result) { if (!is.null(result$passed) && result$passed) { cat(paste0(test, " passed\n")) } else { cat(paste0(test, " failed: ", result$message, "\n")) } } ))cat("\nUsing Custom Reporter:\n")testthat::test_dir(test_dir_path, reporter = CustomReporter$new())

Output:

Using Custom Reporter:
Starting tests...
addition works correctly failed: add(1, 1) not equal to 2.
Equal
addition works correctly failed: add(-1, 1) not equal to 0.
Equal
All tests completed.

Conclusion

Efficient test reporting is essential for maintaining code quality and catching errors early. The testthat package in R provides several reporters that cater to different needs, from minimal output for CI systems to detailed test results for developers. Selecting the right reporter or creating a custom one can streamline the testing process and ensure the code remains clear and reliable.

Test Reporting Strategies with testthatReporter in R-FAQs

What is testthat?

testthat is a popular R package used for writing and running tests to ensure code works correctly.

Why are reporters important in testing?

Reporters show the results of tests in different formats, helping developers quickly understand the outcomes and identify any issues.

How many types of reporters does testthat have?

testthat has several reporters, including Summary, Minimal, Progress, List, and Check reporters.

Which reporter is best for continuous integration (CI) systems?

The Minimal Reporter is best for CI systems because it provides minimal output, making it easier to see important information.

Can custom reporters be created in testthat?

Yes, custom reporters can be created by extending the Reporter class to fit specific needs.

What should be done if the test directory doesn’t exist?

If the test directory doesn’t exist, it can be created using dir.create().

How to run tests with a specific reporter?

Use the test_dir() function with the reporter parameter set to the desired reporter, like this: testthat::test_dir(“path/to/tests”, reporter = testthat::SummaryReporter$new()).

What happens if a test fails?

If a test fails, the reporter will display a message indicating which test failed and why, helping identify and fix issues quickly.