Move some definitions out of util.ts into a new github.ts module

src/github.test.ts

@@ -0,0 +1,69 @@
+import test from "ava";
+
+import * as github from "./github";
+import { setupTests } from "./testing-utils";
+
+setupTests(test);
+
+test("parseGitHubUrl", (t) => {
+  t.deepEqual(github.parseGitHubUrl("github.com"), "https://github.com");
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.com"),
+    "https://github.com",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://api.github.com"),
+    "https://github.com",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.com/foo/bar"),
+    "https://github.com",
+  );
+
+  t.deepEqual(
+    github.parseGitHubUrl("github.example.com"),
+    "https://github.example.com/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.example.com"),
+    "https://github.example.com/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://api.github.example.com"),
+    "https://github.example.com/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.example.com/api/v3"),
+    "https://github.example.com/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.example.com:1234"),
+    "https://github.example.com:1234/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://api.github.example.com:1234"),
+    "https://github.example.com:1234/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.example.com:1234/api/v3"),
+    "https://github.example.com:1234/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.example.com/base/path"),
+    "https://github.example.com/base/path/",
+  );
+  t.deepEqual(
+    github.parseGitHubUrl("https://github.example.com/base/path/api/v3"),
+    "https://github.example.com/base/path/",
+  );
+
+  t.throws(() => github.parseGitHubUrl(""), {
+    message: '"" is not a valid URL',
+  });
+  t.throws(() => github.parseGitHubUrl("ssh://github.com"), {
+    message: '"ssh://github.com" is not a http or https URL',
+  });
+  t.throws(() => github.parseGitHubUrl("http:///::::433"), {
+    message: '"http:///::::433" is not a valid URL',
+  });
+});