diff --git a/lib/app.js b/lib/app.js
index 8563bf2..88a18cd 100644
--- a/lib/app.js
+++ b/lib/app.js
@@ -222,8 +222,8 @@ class App {
           // Generate Istanbul report
           try {
             this.coverage.generate(this.events, `${this.workingDir}/contracts`);
-
-            const json = JSON.stringify(this.coverage.coverage);
+            const relativeMapping = App.makeKeysRelative(this.coverage.coverage, this.workingDir);
+            const json = JSON.stringify(relativeMapping);
             fs.writeFileSync('./coverage.json', json);
 
             collector.add(this.coverage.coverage);
diff --git a/test/assert.js b/test/assert.js
index a5a97eb..2f074c1 100644
--- a/test/assert.js
+++ b/test/assert.js
@@ -8,7 +8,7 @@ const vm = require('./util/vm');
 const assert = require('assert');
 
 describe('asserts and requires', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should cover assert statements as if they are if statements when they pass', done => {
diff --git a/test/comments.js b/test/comments.js
index 53ace54..036d251 100644
--- a/test/comments.js
+++ b/test/comments.js
@@ -6,7 +6,7 @@ const util = require('./util/util.js');
 const solc = require('solc');
 
 describe('comments', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should cover functions even if comments are present immediately after the opening {', () => {
diff --git a/test/conditional.js b/test/conditional.js
index d66d66a..21ad227 100644
--- a/test/conditional.js
+++ b/test/conditional.js
@@ -8,7 +8,7 @@ const vm = require('./util/vm');
 const assert = require('assert');
 
 describe('conditional statements', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should cover a conditional that reaches the consequent (same-line)', done => {
diff --git a/test/expressions.js b/test/expressions.js
index 96ef2bf..fd3558b 100644
--- a/test/expressions.js
+++ b/test/expressions.js
@@ -11,7 +11,7 @@ const path = require('path');
  *     and passing the error to mocha.
  */
 describe('generic expressions', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
 
   it('should compile after instrumenting a single binary expression', () => {
     const contract = util.getCode('expressions/single-binary-expression.sol');
diff --git a/test/function.js b/test/function.js
index e7156ec..dff9745 100644
--- a/test/function.js
+++ b/test/function.js
@@ -14,7 +14,7 @@ const assert = require('assert');
  *     and passing the error to mocha.
  */
 describe('function declarations', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should compile after instrumenting an ordinary function declaration', () => {
diff --git a/test/if.js b/test/if.js
index a779f08..4c8fd82 100644
--- a/test/if.js
+++ b/test/if.js
@@ -8,7 +8,7 @@ const vm = require('./util/vm');
 const assert = require('assert');
 
 describe('if, else, and else if statements', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should cover an if statement with a bracketed consequent', done => {
diff --git a/test/loops.js b/test/loops.js
index b6b8437..6cba5e5 100644
--- a/test/loops.js
+++ b/test/loops.js
@@ -8,7 +8,7 @@ const vm = require('./util/vm');
 const assert = require('assert');
 
 describe('for and while statements', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should cover a for statement with a bracketed body (multiline)', done => {
diff --git a/test/statements.js b/test/statements.js
index 2a38f66..1c3c6e9 100644
--- a/test/statements.js
+++ b/test/statements.js
@@ -14,7 +14,7 @@ const assert = require('assert');
  *     and passing the error to mocha.
  */
 describe('generic statements', () => {
-  const filePath = path.resolve('./test.sol').split('\\').join('/');
+  const filePath = path.resolve('./test.sol');
   const pathPrefix = './';
 
   it('should compile after instrumenting a single statement (first line of function)', () => {