reads trace file line by line

lib/app.js

@@ -2,6 +2,7 @@ const shell = require('shelljs');
 const fs = require('fs');
 const path = require('path');
 const childprocess = require('child_process');
+const readline = require('readline');
 const reqCwd = require('req-cwd');
 const istanbul = require('istanbul');
 const getInstrumentedVersion = require('./instrumentSolidity.js');
@@ -184,14 +185,6 @@ class App {
       shell.exec(command);
       this.testsErrored = shell.error();
       shell.cd('./..');
-    } catch (err) {
-      this.cleanUp(err);
-    }
-
-    // Get events fired during instrumented contracts execution.
-    try {
-      this.events = fs.readFileSync('./allFiredEvents').toString().split('\n');
-      this.events.pop();
     } catch (err) {
       const msg =
       `
@@ -212,25 +205,39 @@ class App {
     const reporter = new istanbul.Reporter();
 
     return new Promise((resolve, reject) => {
-      try {
-        this.coverage.generate(this.events, `${this.workingDir}/contracts`);
-
-        const json = JSON.stringify(this.coverage.coverage);
-        fs.writeFileSync('./coverage.json', json);
-
-        collector.add(this.coverage.coverage);
-        reporter.add('html');
-        reporter.add('lcov');
-        reporter.add('text');
-        reporter.write(collector, true, () => {
-          this.log('Istanbul coverage reports generated');
-          this.cleanUp();
-          resolve();
+      // Get events fired during instrumented contracts execution.
+      const stream = fs.createReadStream(`./allFiredEvents`);
+      stream.on('error', err => this.cleanUp('Event trace could not be read.\n' + err));
+      const reader = readline.createInterface({
+        input: stream,
+      });
+      this.events = [];
+      reader
+        .on('line', line => this.events.push(line))
+        .on('close', () => {
+          // Generate Istanbul report
+          try {
+            // console.log(`got ${this.events.length} events`);
+            this.coverage.generate(this.events, `${this.workingDir}/contracts`);
+
+            const json = JSON.stringify(this.coverage.coverage);
+            fs.writeFileSync('./coverage.json', json);
+
+            collector.add(this.coverage.coverage);
+            reporter.add('html');
+            reporter.add('lcov');
+            reporter.add('text');
+            reporter.write(collector, true, () => {
+              this.log('Istanbul coverage reports generated');
+              this.cleanUp();
+              resolve();
+            });
+          } catch (err) {
+            const msg = 'There was a problem generating the coverage map / running Istanbul.\n';
+            console.log(err.stack);
+            this.cleanUp(msg + err);
+          }
         });
-      } catch (err) {
-        const msg = 'There was a problem generating the coverage map / running Istanbul.\n';
-        this.cleanUp(msg + err);
-      }
     });
   }