Applying jest coverageThreshold to aggregated report - node.js

Question

Problem
I have a Node project with 2 different jest runs that I perform through different npm tasks. They both use the same jest.config.js, which has a declaration for coverageThreshold. I want to apply that threshold to the combined output of the jest runs.
How can I apply a jest coverage threshold to the combined output of multiple test runs?
Background
For reference, see the code for the sample project described below here
Sample project
To illustrate the problem, assume the project has a single file that looks like this:
Code under test
# src/index.js
function run(cond) {
if (cond) {
return "foo";
}
return "bar";
}
module.exports = run;
There are also 2 tests in the project:
Test 1
# src/__tests__/index.group1.test.js
var run = require("../index");
describe("when cond is true", () => {
it("should return 'foo'", () => {
expect(run(true)).toEqual("foo");
});
});
Test 2
# src/__tests__/index.group1.test.js
var run = require("../index");
describe("when cond is false", () => {
it("should return 'bar'", () => {
expect(run(false)).toEqual("bar");
})
});
The test coverage npm scripts in package.json look like this:
"test:group1:coverage": "jest --testPathPattern=group1 --coverage",
"test:group2:coverage": "jest --testPathPattern=group2 --coverage"
Running npm run test:group1:coverage generates:
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 75 | 50 | 100 | 75 | |
index.js | 75 | 50 | 100 | 75 | 5 |
----------|----------|----------|----------|----------|-------------------|
Running npm run test:group2:coverage generates:
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 75 | 50 | 100 | 75 | |
index.js | 75 | 50 | 100 | 75 | 3 |
----------|----------|----------|----------|----------|-------------------|
Combining coverage reports
Based on this post, I can have a separate npm task like this ...
"test:coverage": "npm run test:group1:coverage && mv ./coverage/coverage-final.json ./coverage/coverage-group1-final.json && npm run test:group2:coverage && mv ./coverage/coverage-final.json ./coverage/coverage-group2-final.json && node ./scripts/map-coverage.js"
... to generate a combined coverage report that looks like:
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.js | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
It's all good until this point. The problem arises when trying to apply a coverage threshold to the combined run.
Issue
Now, if I add coverageThreshold to the jest.config.js like this ...
module.exports = {
coverageThreshold: {
global: {
branches: 90,
functions: 90,
lines: 90,
statements: 90,
},
},
};
... and run npm run test:coverage, the tests fails ...
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 75 | 50 | 100 | 75 | |
index.js | 75 | 50 | 100 | 75 | 5 |
----------|----------|----------|----------|----------|-------------------|
Jest: "global" coverage threshold for statements (90%) not met: 75%
Jest: "global" coverage threshold for branches (90%) not met: 50%
Jest: "global" coverage threshold for lines (90%) not met: 75%
... because it first runs group1 tests, which on its own fails to get over the coverage threshold set in jest.config.js. I want to ignore this threshold for individual runs, and only apply them to the combined report.
Note
I know I could split the jest.config.js file into separate ones and apply individual coverage thresholds per test group, but I don't want to manage thresholds individually per test group. I want to measure/apply it to the project as a whole, after all individual test runs have been completed and combined.

Answer 1

Instead of combining the tasks, combine only the pathPattern.
You can try to create a single task for group1 and group2 something like below
"test:commongroup:coverage": "jest --testPathPattern=commonGroup --coverage",
where commonGroup is pattern that includes both group1 and group2.