Allow missing coverage via an environment variable

changelog.md

@@ -2,6 +2,10 @@
 
 ## Next
 
+### Minor
+
+- A truthy `ALLOW_MISSING_COVERAGE` environment variable can now be used with the `coverage-node` CLI to prevent missing coverage from causing the process to exit with code `1`, via [#2](https://github.com/jaydenseric/coverage-node/pull/2).
+
 ### Patch
 
 - Updated dependencies.

coverage-node.mjs

@@ -16,7 +16,8 @@ import reportCoverage from "./reportCoverage.mjs";
 /**
  * Powers the `coverage-node` CLI. Runs Node.js with the given arguments and
  * coverage enabled. An analysis of the coverage is reported to the console, and
- * if coverage isn’t complete the process exits with code `1`.
+ * if coverage is incomplete and there isn’t a truthy `ALLOW_MISSING_COVERAGE`
+ * environment variable the process exits with code `1`.
  * @returns {Promise<void>} Resolves when all work is complete.
  */
 async function coverageNode() {
@@ -41,7 +42,8 @@ async function coverageNode() {
         if (exitCode === 0) {
           const analysis = await analyseCoverage(tempDirPath);
           reportCoverage(analysis);
-          if (analysis.uncovered.length) process.exitCode = 1;
+          if (analysis.uncovered.length && !process.env.ALLOW_MISSING_COVERAGE)
+            process.exitCode = 1;
         } else if (exitCode !== null) process.exitCode = exitCode;
       });
       // coverage ignore next line

coverage-node.test.mjs

@@ -113,57 +113,116 @@ export default (tests) => {
     });
   });
 
-  tests.add("`coverage-node` CLI with 1 uncovered file.", async () => {
-    await disposableDirectory(async (tempDirPath) => {
-      const filePath = join(tempDirPath, "index.mjs");
+  tests.add(
+    "`coverage-node` CLI with 1 uncovered file, `ALLOW_MISSING_COVERAGE` environment variable falsy.",
+    async () => {
+      await disposableDirectory(async (tempDirPath) => {
+        const filePath = join(tempDirPath, "index.mjs");
 
-      await fs.promises.writeFile(filePath, "() => {};");
+        await fs.promises.writeFile(filePath, "() => {};");
 
-      const { stdout, stderr, status, error } = spawnSync(
-        "node",
-        [COVERAGE_NODE_CLI_PATH, filePath],
-        {
-          env: {
-            ...process.env,
-            FORCE_COLOR: "1",
-          },
-        }
-      );
+        const { stdout, stderr, status, error } = spawnSync(
+          "node",
+          [COVERAGE_NODE_CLI_PATH, filePath],
+          {
+            env: {
+              ...process.env,
+              FORCE_COLOR: "1",
+            },
+          }
+        );
 
-      if (error) throw error;
+        if (error) throw error;
 
-      await snapshot(
-        coverageSupported
-          ? stdout.toString()
-          : stdout
+        await snapshot(
+          coverageSupported
+            ? stdout.toString()
+            : stdout
+                .toString()
+                .replace(
+                  process.version,
+                  SNAPSHOT_REPLACEMENT_PROCESS_NODE_VERSION
+                ),
+          new URL(
+            `./test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-falsy-coverage-${
+              coverageSupported ? "supported" : "unsupported"
+            }-stdout.ans`,
+            import.meta.url
+          )
+        );
+
+        if (coverageSupported)
+          await snapshot(
+            stderr
               .toString()
-              .replace(
-                process.version,
-                SNAPSHOT_REPLACEMENT_PROCESS_NODE_VERSION
-              ),
-        new URL(
-          `./test/snapshots/coverage-node/1-uncovered-file-coverage-${
-            coverageSupported ? "supported" : "unsupported"
-          }-stdout.ans`,
-          import.meta.url
-        )
-      );
+              .replace(relative("", filePath), SNAPSHOT_REPLACEMENT_FILE_PATH),
+            new URL(
+              "./test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-falsy-coverage-supported-stderr.ans",
+              import.meta.url
+            )
+          );
+        else strictEqual(stderr.toString(), "");
+
+        strictEqual(status, coverageSupported ? 1 : 0);
+      });
+    }
+  );
+
+  tests.add(
+    "`coverage-node` CLI with 1 uncovered file, `ALLOW_MISSING_COVERAGE` environment variable truthy.",
+    async () => {
+      await disposableDirectory(async (tempDirPath) => {
+        const filePath = join(tempDirPath, "index.mjs");
+
+        await fs.promises.writeFile(filePath, "() => {};");
+
+        const { stdout, stderr, status, error } = spawnSync(
+          "node",
+          [COVERAGE_NODE_CLI_PATH, filePath],
+          {
+            env: {
+              ...process.env,
+              FORCE_COLOR: "1",
+              ALLOW_MISSING_COVERAGE: "1",
+            },
+          }
+        );
+
+        if (error) throw error;
 
-      if (coverageSupported)
         await snapshot(
-          stderr
-            .toString()
-            .replace(relative("", filePath), SNAPSHOT_REPLACEMENT_FILE_PATH),
+          coverageSupported
+            ? stdout.toString()
+            : stdout
+                .toString()
+                .replace(
+                  process.version,
+                  SNAPSHOT_REPLACEMENT_PROCESS_NODE_VERSION
+                ),
           new URL(
-            "./test/snapshots/coverage-node/1-uncovered-file-coverage-supported-stderr.ans",
+            `./test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-truthy-coverage-${
+              coverageSupported ? "supported" : "unsupported"
+            }-stdout.ans`,
             import.meta.url
           )
         );
-      else strictEqual(stderr.toString(), "");
 
-      strictEqual(status, coverageSupported ? 1 : 0);
-    });
-  });
+        if (coverageSupported)
+          await snapshot(
+            stderr
+              .toString()
+              .replace(relative("", filePath), SNAPSHOT_REPLACEMENT_FILE_PATH),
+            new URL(
+              "./test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-truthy-coverage-supported-stderr.ans",
+              import.meta.url
+            )
+          );
+        else strictEqual(stderr.toString(), "");
+
+        strictEqual(status, 0);
+      });
+    }
+  );
 
   tests.add(
     "`coverage-node` CLI with 2 covered, ignored and uncovered files.",

readme.md

@@ -57,7 +57,7 @@ if (false) console.log("Never runs.");
 
 ### Command `coverage-node`
 
-Substitutes the normal `node` command; any [`node` CLI options](https://nodejs.org/api/cli.html#cli_options) can be used to run a test script. If the script doesn’t error a code coverage analysis is reported to the console, and if coverage is incomplete the exit code is `1`.
+Substitutes the normal `node` command; any [`node` CLI options](https://nodejs.org/api/cli.html#cli_options) can be used to run a test script. If the script doesn’t error a code coverage analysis is reported to the console, and if coverage is incomplete and there isn’t a truthy `ALLOW_MISSING_COVERAGE` environment variable the process exits with code `1`.
 
 #### Examples
 
@@ -77,6 +77,16 @@ A [`package.json` script](https://docs.npmjs.com/cli/v8/configuring-npm/package-
 }
 ```
 
+A [`package.json` script](https://docs.npmjs.com/cli/v8/configuring-npm/package-json#scripts) that allows missing coverage:
+
+```json
+{
+  "scripts": {
+    "test": "ALLOW_MISSING_COVERAGE=1 coverage-node test.mjs"
+  }
+}
+```
+
 ## Exports
 
 These ECMAScript modules are published to [npm](https://npmjs.com) and exported via the [`package.json`](./package.json) `exports` field:

test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-truthy-coverage-supported-stderr.ans

@@ -0,0 +1,4 @@
+
+1 file missing coverage:
+
+  <file path>:1:1 → 1:8

test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-truthy-coverage-supported-stdout.ans

@@ -0,0 +1,3 @@
+
+0/1 files covered.
+

test/snapshots/coverage-node/1-uncovered-file-ALLOW_MISSING_COVERAGE-truthy-coverage-unsupported-stdout.ans

@@ -0,0 +1,3 @@
+
+Skipped code coverage as Node.js is <process Node.js version>, v13.3.0+ is supported.
+