Support single file targets, add README docs

README.md

@@ -44,6 +44,7 @@ npx hardhat coverage [command-options]
 | Option <img width=200/> | Example <img width=750/>| Description <img width=1000/> |
 |--------------|------------------------------------|--------------------------------|
 | testfiles  | `--testfiles "test/registry/*.ts"` | Test file(s) to run. (Globs must be enclosed by quotes and use [globby matching patterns][38])|
+| sources | --sources "myFolder" or --sources "myFile.sol" | Path to *single* folder or file to target for coverage. Path is relative to Hardhat's `paths.sources` (usually `contracts/`)) |
 | solcoverjs | `--solcoverjs ./../.solcover.js` | Relative path from working directory to config. Useful for monorepo packages that share settings. (Path must be "./" prefixed) |
 | network    | `--network development` | Use network settings defined in the Hardhat config |
 | temp[<sup>*</sup>][14]       | `--temp build`   | :warning: **Caution** :warning:  Path to a *disposable* folder to store compilation artifacts in. Useful when your test setup scripts include hard-coded paths to a build directory. [More...][14] |

plugins/resources/nomiclabs.utils.js

@@ -30,8 +30,14 @@ function getTestFilePaths(files){
  * @return {HardhatConfig}        updated config
  */
 function normalizeConfig(config, args={}){
+  let sources;
+
+  (args.sources)
+    ? sources = path.join(config.paths.sources, args.sources)
+    : sources = config.paths.sources;
+
   config.workingDir = config.paths.root;
-  config.contractsDir = args.sources? args.sources : config.paths.sources;
+  config.contractsDir = sources;
   config.testDir = config.paths.tests;
   config.artifactsDir = config.paths.artifacts;
   config.logger = config.logger ? config.logger : {log: null};

plugins/resources/plugin.utils.js

@@ -131,8 +131,18 @@ function checkContext(config, tempContractsDir, tempArtifactsDir){
 // =============================
 
 function assembleFiles(config, skipFiles=[]){
-  const targetsPath = path.join(config.contractsDir, '**', '*.{sol,vy}');
-  const targets = shell.ls(targetsPath).map(path.normalize);
+  let targets;
+  let targetsPath;
+
+  // The targets (contractsDir) could actually be a single named file (OR a folder)
+  const extName = path.extname(config.contractsDir);
+
+  if (extName.length !== 0) {
+    targets = [ path.normalize(config.contractsDir) ];
+  } else {
+    targetsPath = path.join(config.contractsDir, '**', '*.{sol,vy}');
+    targets = shell.ls(targetsPath).map(path.normalize);
+  }
 
   skipFiles = assembleSkipped(config, targets, skipFiles);
 

test/units/hardhat/flags.js

@@ -231,17 +231,53 @@ describe('Hardhat Plugin: command line options', function() {
     assert.deepEqual(output, expected);
   })
 
-  it('--sources contract/<fileName>', async function() {
+  it('--sources folder', async function() {
 
     const taskArgs = {
-      testfiles: path.join(
-        hardhatConfig.paths.root,
-        'test/other_contract_a.js'
-      ),
-      sources: path.join(
-        hardhatConfig.paths.root,
-        'contracts/otherContracts'
-      )
+      testfiles: path.join(hardhatConfig.paths.root, 'test/other_contract_a.js'),
+      sources: 'otherContracts'
+    };
+    mock.installFullProject('test-files');
+    mock.hardhatSetupEnv(this);
+
+    await this.env.run("coverage", taskArgs);
+
+    const expected = [
+      {
+        file: mock.pathToContract(hardhatConfig, 'otherContracts/OtherContractA.sol'),
+        pct: 100
+      }
+    ];
+
+    verify.lineCoverage(expected);
+  });
+
+  it('--sources folder/', async function() {
+
+    const taskArgs = {
+      testfiles: path.join(hardhatConfig.paths.root, 'test/other_contract_a.js'),
+      sources: 'otherContracts/'
+    };
+    mock.installFullProject('test-files');
+    mock.hardhatSetupEnv(this);
+
+    await this.env.run("coverage", taskArgs);
+
+    const expected = [
+      {
+        file: mock.pathToContract(hardhatConfig, 'otherContracts/OtherContractA.sol'),
+        pct: 100
+      }
+    ];
+
+    verify.lineCoverage(expected);
+  });
+
+  it('--sources folder/filename.sol', async function() {
+
+    const taskArgs = {
+      testfiles: path.join(hardhatConfig.paths.root, 'test/other_contract_a.js'),
+      sources: 'otherContracts/OtherContractA.sol'
     };
     mock.installFullProject('test-files');
     mock.hardhatSetupEnv(this);