Raise an error when no string/file provided

Intended to fix https://github.com/sass/node-sass/issues/924

lib/index.js

@@ -179,8 +179,9 @@ function getLinefeed(options) {
 function getOptions(options, cb) {
   options = options || {};
   options.sourceComments = options.sourceComments || false;
-  options.data = options.data || null;
-  options.file = getInputFile(options);
+  if (options.hasOwnProperty('file')) {
+    options.file = getInputFile(options);
+  }
   options.outFile = getOutputFile(options);
   options.includePaths = (options.includePaths || []).join(path.delimiter);
   options.precision = parseInt(options.precision) || 5;
@@ -351,7 +352,13 @@ module.exports.render = function(options, cb) {
     });
   }
 
-  return options.data ? binding.render(options) : binding.renderFile(options);
+  if (options.data) {
+    binding.render(options);
+  } else if (options.file) {
+    binding.renderFile(options);
+  } else {
+    cb({status: 3, message: 'No input specified: provide a file name or a source string to process' });
+  }
 };
 
 /**
@@ -398,7 +405,15 @@ module.exports.renderSync = function(options) {
     });
   }
 
-  var status = options.data ? binding.renderSync(options) : binding.renderFileSync(options);
+  var status;
+  if (options.data) {
+     status = binding.renderSync(options);
+  } else if (options.file) {
+     status = binding.renderFileSync(options);
+  } else {
+     throw new Error('No input specified: provide a file name or a source string to process');
+  }
+
   var result = options.result;
 
   if (status) {

test/api.js

@@ -76,6 +76,22 @@ describe('api', function() {
       });
     });
 
+    it('should NOT compile empty data string', function(done) {
+      sass.render({
+        data: ''
+      }, function(error) {
+        assert.equal(error.message, 'No input specified: provide a file name or a source string to process');
+        done();
+      });
+    });
+
+    it('should NOT compile without parameters', function(done) {
+      sass.render({ }, function(error) {
+        assert.equal(error.message, 'No input specified: provide a file name or a source string to process');
+        done();
+      });
+    });
+
     it('should compile sass to css using indented syntax', function(done) {
       var src = read(fixture('indent/index.sass'), 'utf8');
       var expected = read(fixture('indent/expected.css'), 'utf8').trim();
@@ -1074,6 +1090,20 @@ describe('api', function() {
       done();
     });
 
+    it('should NOT compile empty data string', function(done) {
+      assert.throws(function() {
+        sass.renderSync({ data: '' });
+      }, /No input specified: provide a file name or a source string to process/ );
+      done();
+    });
+
+    it('should NOT compile without any input', function(done) {
+      assert.throws(function() {
+        sass.renderSync({});
+      }, /No input specified: provide a file name or a source string to process/);
+      done();
+    });
+
     it('should throw error for bad input', function(done) {
       assert.throws(function() {
          sass.renderSync('somestring');

test/lowlevel.js

@@ -12,6 +12,90 @@ describe('lowlevel', function() {
     done();
   });
 
+  it('data context with options.data not provided', function(done) {
+    var options =  { 
+      /* data: */
+      sourceComments: false,
+      file: null,
+      outFile: null,
+      includePaths: '',
+      precision: 5,
+      sourceMap: null,
+      style: 0,
+      indentWidth: 2,
+      indentType: 0,
+      linefeed: '\n',
+      result: { stats: {} } };
+
+    binding.renderSync(options);
+    assert(/Data context created without a source string/.test(options.result.error), 
+          'Should fail with error message "Data context created without a source string"');
+    done();
+  });
+
+  it('data context with both options.data and options.file not provided', function(done) {
+    var options =  { 
+      /* data: */
+      sourceComments: false,
+      /* file: null, */
+      outFile: null,
+      includePaths: '',
+      precision: 5,
+      sourceMap: null,
+      style: 0,
+      indentWidth: 2,
+      indentType: 0,
+      linefeed: '\n',
+      result: { stats: {} } };
+
+    binding.renderSync(options);
+    assert(/Data context created without a source string/.test(options.result.error), 
+          'Should fail with error message "Data context created without a source string"');
+    done();
+  });
+
+  it('file context with both options.data and options.file not provided', function(done) {
+    var options =  { 
+      /* data: */
+      sourceComments: false,
+      /* file: null, */
+      outFile: null,
+      includePaths: '',
+      precision: 5,
+      sourceMap: null,
+      style: 0,
+      indentWidth: 2,
+      indentType: 0,
+      linefeed: '\n',
+      result: { stats: {} } };
+
+    binding.renderFileSync(options);
+    assert(/File context created without an input path/.test(options.result.error), 
+          'Should fail with error message "File context created without an input path"');
+    done();
+  });
+
+  it('file context with options.file not provided, options.data given', function(done) {
+    var options =  { 
+      data: 'div { width: 10px; } ',
+      sourceComments: false,
+      /* file: null, */
+      outFile: null,
+      includePaths: '',
+      precision: 5,
+      sourceMap: null,
+      style: 0,
+      indentWidth: 2,
+      indentType: 0,
+      linefeed: '\n',
+      result: { stats: {} } };
+
+    binding.renderFileSync(options);
+    assert(/File context created without an input path/.test(options.result.error), 
+          'Should fail with error message "File context created without an input path"');
+    done();
+  });
+
   it('fail with options.result not provided', function(done) {
     var options =  { data: 'div { width: 10px; } ',
       sourceComments: false,
@@ -96,7 +180,26 @@ describe('lowlevel', function() {
   });
 
   it('options.indentWidth not provided', function(done) {
-    var options =  { data: 'div { width: 10px; } ',
+    var options =  { data: 'div { width: 10px; }',
+      sourceComments: false,
+      file: null,
+      outFile: null,
+      includePaths: '',
+      precision: 5,
+      sourceMap: null,
+      style: 0,
+      /* indentWidth */
+      indentType: 0,
+      linefeed: '\n',
+      result: { stats: {} } };
+
+      binding.renderSync(options);
+      assert(options.result.css);
+    done();
+  });
+
+  it('empty data string', function(done) {
+    var options =  { data: '',
       sourceComments: false,
       file: null,
       outFile: null,
@@ -110,8 +213,30 @@ describe('lowlevel', function() {
       result: { stats: {} } };
 
       binding.renderSync(options);
+      assert(/empty source string/.test(options.result.error), 
+          'Should fail with error message "Data context created with empty source string"');
     done();
   });
 
 
+  it('empty file string', function(done) {
+    var options =  { 
+      sourceComments: false,
+      file: '',
+      outFile: null,
+      includePaths: '',
+      precision: 5,
+      sourceMap: null,
+      style: 0,
+      /* indentWidth */
+      indentType: 0,
+      linefeed: '\n',
+      result: { stats: {} } };
+
+      binding.renderFileSync(options);
+      assert(/empty input path/.test(options.result.error), 
+          'Should fail with error message "File context created with empty input path"');
+    done();
+  });
+
 }); // lowlevel