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Run Cadence tests

The Flow CLI provides a command to run Cadence tests.


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flow test /path/to/test_script.cdc

⚠️ The test command expects configuration to be initialized. See flow init command.

Example Usage​

A simple Cadence script test_script.cdc, which has a test case for running a cadence script on-chain:


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import Test
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pub let blockchain = Test.newEmulatorBlockchain()
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pub fun testSumOfTwo() {
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let scriptResult = blockchain.executeScript(
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"pub fun main(a: Int, b: Int): Int { return a + b }",
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[2, 3]
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)
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Test.expect(scriptResult, Test.beSucceeded())
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let sum = scriptResult.returnValue! as! Int
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Test.assertEqual(5, sum)
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}

The above test-script can be run with the CLI as follows, and the test results will be printed on the console.


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$ flow test test_script.cdc
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Test results: "test_script.cdc"
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- PASS: testSumOfTwo

To learn more about writing tests in Cadence, take a look at the Cadence testing framework.

Flags​

Coverage​

  • Flag: --cover
  • Default: false

Use the cover flag to calculate coverage report for the code being tested.


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$ flow test --cover test_script.cdc
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Test results: "test_script.cdc"
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- PASS: testSumOfTwo
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Coverage: 96.5% of statements

Coverage Report File​

  • Flag: --coverprofile
  • Valid inputs: valid filename and extension
  • Default: "coverage.json"

Use the coverprofile to specify the filename where the calculated coverage report is to be written. Supported filename extensions are .json and .lcov.


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$ flow test --cover test_script.cdc
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$ cat coverage.json
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$ flow test --cover --coverprofile="coverage.lcov" test_script.cdc
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$ cat coverage.lcov

Coverage Code Type​

  • Flag: --covercode
  • Valid inputs: "all", "contracts"
  • Default: "all"

Use the covercode flag to calculate coverage report only for certain types of code. A value of "contracts" will exclude scripts and transactions from the coverage report.


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$ flow test --cover --covercode="contracts" test_script.cdc
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Test results: "tests/test_script.cdc"
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- PASS: testSumOfTwo
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There are no statements to cover

Since we did not use any contracts in our sample test script, there is no coverage percentage to be reported.