Add new hook and make temporary contracts directory configurable

docs/advanced.md

@@ -34,6 +34,7 @@ The stages/hooks are (in order of execution):
 
 | Stage                                  | Post-stage hook    |
 |----------------------------------------|--------------------|
+| Before compiling                       | onPreCompile       |
 | Launch server                          | onServerReady      |
 | Instrument and compile contracts       | onCompileComplete  |
 | Run tests using instrumented artifacts | onTestsComplete    |
@@ -85,6 +86,14 @@ This option allows you to avoid that but it's important to realise that the temp
 folder is **automatically deleted** when coverage completes. You shouldn't use it if your preferred
 build target contains information you want to preserve between test runs.
 
+## Setting a custom temporary contracts directory
+
+A custom disposable folder to be used for the contracts can be specified by setting the
+```
+coverage_contracts_temp
+```
+property in the configuration file. If not set, this directory defaults to `.coverage_contracts`.
+
 ## Reducing the instrumentation footprint
 
 If your project is very large or if you have logic that's gas sensitive, it can be useful to

lib/api.js

@@ -36,6 +36,7 @@ class API {
     this.onTestsComplete = config.onTestsComplete       || this.defaultHook;
     this.onCompileComplete = config.onCompileComplete   || this.defaultHook;
     this.onIstanbulComplete = config.onIstanbulComplete || this.defaultHook;
+    this.onPreCompile = config.onPreCompile             || this.defaultHook;
 
     this.server = null;
     this.defaultPort = 8555;

plugins/resources/plugin.utils.js

@@ -94,7 +94,7 @@ function toRelativePath(pathToFile, pathToParent){
 function getTempLocations(config){
   const contractsRoot = path.parse(config.contractsDir).dir
   const cwd = config.workingDir;
-  const contractsDirName = '.coverage_contracts';
+  const contractsDirName = config.coverage_contracts_temp || '.coverage_contracts';
   const artifactsDirName = config.temp || '.coverage_artifacts';
 
   return {

plugins/truffle.plugin.js

@@ -93,6 +93,9 @@ async function plugin(config){
     config.all = true;
     config.compilers.solc.settings.optimizer.enabled = false;
 
+    // Run pre-compile hook;
+    await api.onPreCompile(config);
+
     // Compile Instrumented Contracts
     await truffle.contracts.compile(config);
     await api.onCompileComplete(config);

test/integration/projects/test-files/.solcover.js

@@ -5,6 +5,7 @@ module.exports = {
   skipFiles: ['Migrations.sol'],
   silent: process.env.SILENT ? true : false,
   istanbulReporter: ['json-summary', 'text'],
+  onPreCompile: fn.bind(null, 'running onPreCompile'),
   onServerReady: fn.bind(null, 'running onServerReady'),
   onTestsComplete: fn.bind(null, 'running onTestsComplete'),
   onCompileComplete: fn.bind(null, 'running onCompileComplete'),

test/units/truffle/standard.js

@@ -420,6 +420,7 @@ describe('Truffle Plugin: standard use cases', function() {
     await plugin(truffleConfig);
 
     assert(
+      mock.loggerOutput.val.includes('running onPreCompile')     &&
       mock.loggerOutput.val.includes('running onServerReady')     &&
       mock.loggerOutput.val.includes('running onTestsComplete')   &&
       mock.loggerOutput.val.includes('running onCompileComplete') &&