add unified coverage maps, and fix issue when using coverage without …

…instrumentation

lib/vows/coverage/report-json.js

@@ -0,0 +1,54 @@
+var sys  = require('sys'),
+    fs   = require('fs'),
+    file = require('./file');
+
+this.name = 'coverage-report-json';
+
+this.report = function (coverageMap) {
+    var output = {
+        meta: {
+            "generator":        "vowsjs",
+            "generated":        new Date().toString(),
+            "instrumentation":  "node-jscoverage",
+            "file-version":     "1.0"
+        },
+        files:     [ ],
+        coverage:  [ ]
+    };
+
+
+    for (var filename in coverageMap) {
+        if (coverageMap.hasOwnProperty(filename)) {
+            var data = file.coverage(filename, coverageMap[filename]);
+
+            var coverage = {
+                file:      filename,
+                coverage:  data.coverage.toFixed(2),
+                hits:      data.hits,
+                misses:    data.misses,
+                sloc:      data.sloc,
+                source:    { }
+            };
+
+            for (var i = 0; i < data.source.length; i++) {
+                coverage.source[i + 1] = {
+                    line:     data.source[i].line,
+                    coverage: data.source[i].coverage
+                };
+            }
+
+            output.coverage.push(coverage);
+
+            output.files.push(filename);
+        }
+    }
+
+    try {
+        out  = fs.openSync("coverage.json", "w");
+        fs.writeSync(out, JSON.stringify(output));
+        fs.close(out);
+    } catch (error) {
+        sys.print("Error: Unable to write to file coverage.json\n");
+        return;
+    }
+};