Add MD029 with tests.

lib/rules.js

@@ -333,6 +333,30 @@ module.exports = [
     }
   },
 
+  {
+    "name": "MD029",
+    "desc": "Ordered list item prefix",
+    "func": function MD029(params, errors) {
+      var style = params.options.style || "one";
+      var number = 0;
+      params.tokens.forEach(function forToken(token) {
+        if (token.type === "ordered_list_open") {
+          number = 1;
+        } else if (token.type === "ordered_list_close") {
+          number = 0;
+        } else if ((token.type === "list_item_open") && number) {
+          var regex = new RegExp("^\\s*" + String(number) + "\\. ");
+          if (!regex.test(token.line)) {
+            errors.push(token.lineNumber);
+          }
+          if (style === "ordered") {
+            number++;
+          }
+        }
+      });
+    }
+  },
+
   {
     "name": "MD031",
     "desc": "Fenced code blocks should be surrounded by blank lines",

test/lists_without_blank_lines.json

@@ -1,4 +1,5 @@
 {
   "default": true,
-  "MD004": false
+  "MD004": false,
+  "MD029": false
 }

test/ordered_list_item_prefix.md

@@ -0,0 +1,13 @@
+Good list:
+
+1. Do this.
+1. Do that.
+1. ???
+1. Profit!
+
+Bad list:
+
+1. Do this.
+2. Do nothing. {MD029}
+3. ??? {MD029}
+4. Failed! {MD029}

test/ordered_list_item_prefix_ordered.json

@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD029": {
+    "style": "ordered"
+  }
+}

test/ordered_list_item_prefix_ordered.md

@@ -0,0 +1,13 @@
+Good list:
+
+1. Do this.
+2. Do that.
+3. ???
+4. Profit!
+
+Bad list:
+
+1. Do this.
+1. Do nothing. {MD029}
+1. ??? {MD029}
+1. Failed! {MD029}