fix(reporter): Disable source maps for URLs without line number

There is no way to resolve them in this case anyway. Fixes #1274.

lib/reporter.js

@@ -49,7 +49,7 @@ var createErrorFormatter = function (basePath, emitter, SourceMapConsumer) {
 
       var file = findFile(path)
 
-      if (file && file.sourceMap) {
+      if (file && file.sourceMap && line) {
         line = parseInt(line || '0', 10)
 
         column = parseInt(column, 10)

test/unit/reporter.spec.js

@@ -75,12 +75,15 @@ describe('reporter', () => {
     })
 
     describe('source maps', () => {
+      var originalPositionForCallCount = 0
+
       class MockSourceMapConsumer {
         constructor (sourceMap) {
           this.source = sourceMap.content.replace('SOURCE MAP ', '/original/')
         }
 
         originalPositionFor (position) {
+          originalPositionForCallCount++
           if (position.line === 0) {
             throw new TypeError('Line must be greater than or equal to 1, got 0')
           }
@@ -93,6 +96,10 @@ describe('reporter', () => {
         }
       }
 
+      beforeEach(() => {
+        originalPositionForCallCount = 0
+      })
+
       MockSourceMapConsumer.GREATEST_LOWER_BOUND = 1
       MockSourceMapConsumer.LEAST_UPPER_BOUND = 2
 
@@ -156,6 +163,22 @@ describe('reporter', () => {
         })
       })
 
+      it('should not try to use source maps when no line is given', done => {
+        formatError = m.createErrorFormatter('/some/base', emitter, MockSourceMapConsumer)
+        var servedFiles = [new File('/some/base/a.js'), new File('/some/base/b.js')]
+        servedFiles[0].sourceMap = {content: 'SOURCE MAP a.js'}
+        servedFiles[1].sourceMap = {content: 'SOURCE MAP b.js'}
+
+        emitter.emit('file_list_modified', {served: servedFiles})
+
+        _.defer(() => {
+          var ERROR = 'at http://localhost:123/base/b.js'
+          expect(formatError(ERROR)).to.equal('at /some/base/b.js\n')
+          expect(originalPositionForCallCount).to.equal(0)
+          done()
+        })
+      })
+
       describe('Windows', () => {
         formatError = null
         var servedFiles = null