Find Test Classes That Cover a Specific Salesforce Apex Class

 When troubleshooting Apex code coverage, especially during deployments, it can be useful to identify which test classes currently contribute coverage to a specific Apex class or trigger.

Salesforce exposes this information through the Tooling API ApexCodeCoverage object. ApexClassOrTriggerId identifies the class or trigger being tested, while ApexTestClassId identifies the test class generating the coverage. [developer....sforce.com]

1. Get the Apex Class ID

Use the Tooling API to find the target class:

SELECT Id, Name

FROM ApexClass

WHERE Name = 'TargetApexClass'

Example:

01pXXXXXXXXXXXXXXX

2. Find Test Classes Providing Coverage

Query ApexCodeCoverage using the class ID:

SELECT

    ApexClassOrTriggerId,

    ApexTestClassId,

    NumLinesCovered,

    NumLinesUncovered

FROM ApexCodeCoverage

WHERE ApexClassOrTriggerId = '01pXXXXXXXXXXXXXXX'

NumLinesCovered and NumLinesUncovered indicate how much of the target class was exercised by the corresponding test execution. [developer....sforce.com]

3. Return Test Class Names

Instead of working with IDs, include the relationship fields:

SELECT

    ApexClassOrTriggerId,

    ApexClassOrTrigger.Name,

    ApexTestClassId,

    ApexTestClass.Name,

    TestMethodName,

    NumLinesCovered,

    NumLinesUncovered

FROM ApexCodeCoverage

WHERE ApexClassOrTriggerId = '01pXXXXXXXXXXXXXXX'

ORDER BY ApexTestClass.Name

Example output:

TargetApexClass

    TargetApexClass_Test

    ServiceHandler_Test

    BatchProcessor_Test

    IntegrationService_Test

The same test class may appear multiple times because ApexCodeCoverage can contain multiple coverage records associated with different test executions or methods. TestMethodName can be used to identify the individual method. [developer....sforce.com]

For deployment purposes, extract the unique ApexTestClass.Name values.

4. Check Overall Coverage for the Class

To check aggregate coverage instead of individual contributing tests, query ApexCodeCoverageAggregate:

SELECT

    ApexClassOrTriggerId,

    ApexClassOrTrigger.Name,

    NumLinesCovered,

    NumLinesUncovered

FROM ApexCodeCoverageAggregate

WHERE ApexClassOrTriggerId = '01pXXXXXXXXXXXXXXX'

ApexCodeCoverageAggregate represents aggregate coverage results for an Apex class or trigger. [developer....sforce.com]

Coverage percentage can be calculated as:

NumLinesCovered /

(NumLinesCovered + NumLinesUncovered) * 100

Salesforce defines Apex coverage percentage using this covered-lines-to-total-executable-lines calculation. [developer....sforce.com]

Important Distinction

Use:

ApexCodeCoverage

to answer:

Which test classes exercise this Apex class?

Use:

ApexCodeCoverageAggregate

to answer:

What is the combined coverage of this Apex class?

The ApexCodeCoverage results should be treated as current coverage relationships, not permanent code dependencies. Coverage data reflects tests that have executed and the coverage information currently stored in the org. [developer....sforce.com], [help.salesforce.com]

Deployment Use Case

When an Apex deployment fails due to insufficient coverage:

1. Identify the target Apex class ID.
2. Query ApexCodeCoverage.
3. Extract unique ApexTestClass.Name values.
4. Review or include the relevant tests in the deployment test configuration.
5. Query ApexCodeCoverageAggregate to verify the resulting class coverage.

This provides a quick way to identify existing tests that exercise a target Apex class before creating additional test classes.