How do I run a single test using Jest

Question

I have a test  works with nested children  within the file fix-order-test js   Running the below runs all the tests in the file   jest fix-order-test   How do I run only a single test  The below does not work as it searches for a file of the regex specified   jest  works with nested children

User · Answer

With the latest Jest version  you can use one of the following to only run one test  and the same for a test suite  it only  test 1        gt       test only  test 1        gt       fit  test 1        gt       jest  test 1  may work too if the test name is unique

User · Answer

Use  npm run test -- test-name  This will only work if your test specification name is unique  The code above would reference a file with this name  test-name component spec ts

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Jest documentation recommends the following      If a test is failing  one of the first things to check should be   whether the test is failing when it s the only test that runs  In Jest   it s simple to run only one test - just temporarily change that test   command to a test only   test only  this will be the only test that runs        gt       expect true  toBe false         or   it only  this will be the only test that runs        gt       expect true  toBe false

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As mentioned in other answers  test only merely filters out other tests in the same file  So tests in other files would still run   So to run a single test  there are two approaches    Option 1  If your test name is unique  you can enter t while in watch mode and enter the name of the test you d like to run  Option 2    Hit p while in watch mode to enter a regex for the filename you d like to run   Relevant commands like this are displayed when you run Jest in watch mode   Change it to it only on the test you d like to run     With either of the approaches above  Jest will only run the single test in the file you ve specified

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Just a little add-on  because it seems there was kind of a fight if to use   node modules  bin jest -i     or just jest -i     or npm test -- -i      Just calling jest works if you have it installed globally  as with npm install -g jest   a not-so-clean way of handling dependencies If you have Jest installed only locally in the package and want to call the Jest script without the npm script detour  you can use npx jest -i       gt  this is exactly what npx is for  It saves you from writing   node modules  bin

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Full command to run a single Jest test Command  node  lt path-to-jest gt  -i  lt you-test-file gt  -c  lt jest-config gt  -t  quot  lt test-block-name gt  quot    lt path-to-jest gt    Windows  node modules jest bin jest js Others  node modules  bin jest   -i  lt you-test-file gt   path to the file with tests  js or ts  -c  lt jest-config gt   path to a separate Jest config file  JSON   if you keep your Jest configuration in package json  you don t have to specify this parameter  Jest will find it without your help  -t  lt the-name-of-test-block gt   actually it s a name  the first parameter  of describe       it       or test      block    Example  describe  quot math tests quot        gt       it  quot 1   1   2 quot        gt        expect 1   1  toBe 2            it  quot -1   -1     -1 quot        gt        expect -1   -1  not toBe -1               So  the command node node modules jest bin jest js -i test math-tests js -c test tests-config json -t  quot 1   1   2 quot   will test it  quot 1   1   2 quot         but if you change the -t parameter to  quot math tests quot  then it will run both tests from the describe  quot math tests quot       block  Remarks   For Windows  replace node modules  bin jest with node modules jest bin jest js  This approach allows you to debug the running script  To enable debugging add  --inspect-brk  parameter to the command    Running a single Jest test via NPM scripts in  package json  Having Jest installed  you can simplify the syntax of this command  above  by using NPM scripts  In  quot package json quot  add a new script to the  quot scripts quot  section   quot scripts quot        quot test math quot    quot jest -i test my-tests js -t   quot math tests  quot  quot      In this case  we use an alias  jest  instead of writing the full path to it  Also  we don t specify the configuration file path since we can place it in  quot package json quot  as well and Jest will look into it by default  Now you can run the command  npm run test math  And the  quot math tests quot  block with two tests will be executed  Or  of course  you can specify one particular test by its name  Another option would be to pull the  lt the-name-of-test-block gt  parameter outside the  quot test math quot  script and pass it from the NPM command  package json   quot scripts quot        quot test math quot    quot jest -i test my-tests js -t quot      Command  npm run test math  quot math tests quot  Now you can manage the name of the run test s  with a much shorter command  Remarks   The  jest  command will work with NPM scripts because   npm makes  quot   node modules  bin quot  the first entry in the PATH environment variable when running any lifecycle scripts  so this will work fine  even if your program is not globally installed  NPM blog  2  This approach doesn t seem to allow debugging because Jest is run via its binary CLI  not via node    Running a selected Jest test in Visual Studio Code If you are using Visual Studio Code you can take advantage of it and run the currently selected test  in the code editor  by pressing the F5 button  To do this  we will need to create a new launch configuration block in the  quot  vscode launch json quot  file  In that configuration  we will use predefined variables which are substituted with the appropriate  unfortunately not always  values when running  Of all available we are only interested in these     relativeFile  - the current opened file relative to   workspaceFolder    selectedText  - the current selected text in the active file  But before writing out the launch configuration we should add the  test  script in our  package json   if we haven t done it yet   File package json   quot scripts quot        quot test quot    quot jest quot     Then we can use it in our launch configuration  Launch configuration       quot type quot    quot node quot      quot request quot    quot launch quot      quot name quot    quot Run selected Jest test quot      quot runtimeExecutable quot    quot npm quot      quot runtimeArgs quot          quot run-script quot        quot test quot          quot args quot          quot -- quot        quot -i quot        quot   relativeFile  quot        quot -t quot        quot   selectedText  quot          quot console quot    quot integratedTerminal quot      It actually does the same as the commands described earlier in this answer  Now that everything is ready  we can run any test we want without having to rewrite the command parameters manually  Here s all you need to do   Select currently created launch config in the debug panel    Open the file with tests in the code editor and select the name of the test you want to test  without quotation marks     Press F5 button    And voil    Now to run any test you want  Just open it in the editor  select its name  and press F5  Unfortunately  it won t be  quot voil   quot  on a Windows machines because they substitute  who knows why  the   relativeFile  variable with the path having reversed slashes and Jest wouldn t understand such a path  Remarks   To run under the debugger  don t forget to add the  --inspect-brk  parameter  In this configuration example  we don t have the Jest configuration parameter assuming that it s included in  package json

User · Answer

npm test   tests   filename test ts - to run a single file  test only  check single test        gt    expect true  toBe true     - to run a single test case test skip  to skip testcase       gt   expect false  toBe false     - to skip a test case

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Here is my take    node modules  bin jest --config test jest-unit-config json --runInBand src components OpenForm OpenForm spec js -t  show expanded   Notes     node modules  bin     is a wonderful way  to access the locally installed Jest  or Mocha or     binary that came with the locally installed package   Yes  in your npm scripts you can jest with nothing before  but this is handy on command line     that s also a good start for your debugging config  whichever IDE you are using     Your project might not have a set of configuration options  But if it does  peek into the scripts in package json   this is  what you need  --runInBand     as said  don t know about your configuration  but if you concentrate on developing fixing a single test  you rather do not want to deal with web workers    Yes  you can give the whole  explicit path to your file Optionally  you can use -t to not run all tests in that file  but only a single one  here  the one  that has something with    show expanded    in its name   Same effect can be achieved by glueing  only   into that file

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In Visual Studio Code  this lets me run debug only one Jest test  with breakpoints  Debugging tests in Visual Studio Code My launch json file has this inside       quot version quot    quot 0 2 0 quot      quot configurations quot                  quot type quot    quot node quot          quot request quot    quot launch quot          quot name quot    quot Jest All quot          quot program quot    quot   workspaceFolder  node modules  bin jest quot          quot args quot     quot --runInBand quot           quot console quot    quot integratedTerminal quot          quot internalConsoleOptions quot    quot neverOpen quot          quot windows quot              quot program quot    quot   workspaceFolder  node modules jest bin jest quot                               quot type quot    quot node quot          quot request quot    quot launch quot          quot name quot    quot Jest Current File quot          quot program quot    quot   workspaceFolder  node modules  bin jest quot          quot args quot     quot   relativeFile  quot           quot console quot    quot integratedTerminal quot          quot internalConsoleOptions quot    quot neverOpen quot          quot windows quot              quot program quot    quot   workspaceFolder  node modules jest bin jest quot                        And this in file package json     quot scripts quot          quot test quot    quot jest quot        To run one test  in that test  change test  or it  to test only  or it only   To run one test suite  several tests   change describe to describe only  Set breakpoint s  if you want  In Visual Studio Code  go to Debug View  Shift   Cmd   D or Shift   Ctrl   D   From the dropdown menu at top  pick Jest Current File  Click the green arrow to run that test

User · Answer

I took me a while to find this so I d like to add it here for people like me who use yarn  yarn test -i  quot src components folderX folderY     Filename ts quot  -t  quot name of test quot   So filename after -i and testname after -t

User · Answer

From the command line  use the --testNamePattern or -t flag  jest -t  fix-order-test   This will only run tests that match the test name pattern you provide  It s in the Jest documentation  Another way is to run tests in watch mode  jest --watch  and then press P to filter the tests by typing the test file name or T to run a single test name   If you have an it inside of a describe block  you have to run jest -t   lt describeString gt   lt itString gt

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There is now a nice Jest plugin for this called jest-watch-typeahead it makes this process much simpler

User · Answer

As said a previous answer  you can run the command jest -t  fix-order-test   If you have an it inside of a describe block  you have to run jest -t   lt describeString gt   lt itString gt

User · Answer

If you have jest running as a script command  something like npm test  you need to use the following command to make it work   npm test -- -t  fix order test

User · Answer

You can also use f or x to focus or exclude a test  For example  fit  only this test will run        gt       expect true  toBe false        it  this test will not run        gt       expect true  toBe false        xit  this test will be ignored        gt       expect true  toBe false

[jestjs] How do I run a single test using Jest?

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