Convert from tape test harness to ava, address minor declaration file issue.

test/markdownlint-test-extra.js

@@ -5,40 +5,37 @@
 const fs = require("fs");
 const path = require("path");
 const globby = require("globby");
-const tape = require("tape");
-require("tape-player");
+const test = require("ava").default;
 const markdownlint = require("../lib/markdownlint");
-const { utf8Encoding } = require("../helpers");
 
 // Simulates typing each test file to validate handling of partial input
 const files = fs.readdirSync("./test");
 files.filter((file) => /\.md$/.test(file)).forEach((file) => {
   const strings = {};
-  let content = fs.readFileSync(path.join("./test", file), utf8Encoding);
+  let content = fs.readFileSync(path.join("./test", file), "utf8");
   while (content) {
     strings[content.length.toString()] = content;
     content = content.slice(0, -1);
   }
-  tape(`type ${file}`, (test) => {
-    test.plan(1);
+  test(`type ${file}`, (t) => {
+    t.plan(1);
     markdownlint.sync({
       // @ts-ignore
       strings,
       "resultVersion": 0
     });
-    test.pass();
-    test.end();
+    t.pass();
   });
 });
 
 // Parses all Markdown files in all package dependencies
-tape("parseAllFiles", (test) => {
-  test.plan(1);
+test.cb("parseAllFiles", (t) => {
+  t.plan(1);
   const options = {
     "files": globby.sync("**/*.{md,markdown}")
   };
   markdownlint(options, (err) => {
-    test.ifError(err);
-    test.end();
+    t.falsy(err);
+    t.end();
   });
 });