refactor: stop using external git repo for tests

Author: Simon Renoult

.gitmodules

@@ -25,7 +25,7 @@
     "prepare": "npm run lint && npm run build",
     "postversion": "git push --tags",
     "pretest": "npm run lint",
-    "test": "mocha --require ts-node/register test/**/*.ts",
+    "test": "mocha --timeout=5000 --require ts-node/register test/**/*.ts",
     "test:ci": "nyc --reporter=lcov npm test"
   },
   "keywords": [

package.json

@@ -0,0 +1,50 @@
+import { tmpdir } from "os";
+import { sep } from "path";
+import { existsSync, mkdirSync, rmdirSync } from "fs";
+import { execSync } from "child_process";
+import VersionedFileFixture from "./versioned-file.fixture";
+
+export default class TestRepositoryFixture {
+  private readonly systemTemporaryDirectory = tmpdir();
+  public static readonly testRepositoryName = "code-complexity-test-directory";
+
+  public readonly location: string;
+  private files: {
+    name: string;
+    commits?: number;
+    lines?: number;
+    date?: string;
+  }[] = [];
+
+  constructor() {
+    this.location = `${this.systemTemporaryDirectory}${sep}${TestRepositoryFixture.testRepositoryName}`;
+  }
+
+  addFile(args: {
+    name: string;
+    commits?: number;
+    lines?: number;
+    date?: string;
+  }): this {
+    this.files.push(args);
+    return this;
+  }
+
+  public writeOnDisk(): this {
+    if (existsSync(this.location)) {
+      rmdirSync(this.location, { recursive: true });
+    }
+    mkdirSync(this.location);
+    execSync(`git -C ${this.location} init`);
+
+    this.files.forEach((f) => {
+      new VersionedFileFixture(this.location)
+        .withName(f.name)
+        .containing({ lines: f.lines || 1 })
+        .committed({ times: f.commits || 1, date: f.date })
+        .writeOnDisk();
+    });
+
+    return this;
+  }
+}

test/code-complexity-fixture

@@ -0,0 +1,74 @@
+import { execSync } from "child_process";
+import { appendFileSync, writeFileSync } from "fs";
+import { sep } from "path";
+
+export default class VersionedFileFixture {
+  constructor(private readonly repositoryLocation: string) {}
+
+  private name = "example.js";
+  private numberOfLinesInFile = 10;
+  private numberOfCommitsForFile = 10;
+  private commitDate?: string;
+
+  withName(name: string): VersionedFileFixture {
+    this.name = name;
+    return this;
+  }
+
+  containing(args: { lines: number }): VersionedFileFixture {
+    this.numberOfLinesInFile = args.lines;
+    return this;
+  }
+
+  committed(args: { times: number; date?: string }): VersionedFileFixture {
+    this.numberOfCommitsForFile = args.times;
+    this.commitDate = args.date;
+    return this;
+  }
+
+  writeOnDisk(): void {
+    for (let i = 0; i < this.numberOfCommitsForFile; i++) {
+      if (i === 0) {
+        this.createFileWithContentInRepository(this.name);
+        this.addFileToRepository();
+      } else {
+        this.modifyFileWithoutChangingItsLength(i);
+      }
+      this.commitFile(i);
+    }
+  }
+
+  private commitFile(i: number): void {
+    const commitMessage = `"${this.name}: commit #${i + 1}"`;
+    const command = this.commitDate
+      ? `GIT_COMMITTER_DATE="${this.commitDate}" git -C ${this.repositoryLocation} commit --all --message=${commitMessage} --date=${this.commitDate}`
+      : `git -C ${this.repositoryLocation} commit --all --message=${commitMessage}`;
+    try {
+      execSync(command);
+    } catch (e) {
+      console.log(e.stdout.toString());
+      throw e;
+    }
+  }
+
+  private modifyFileWithoutChangingItsLength(i: number): void {
+    appendFileSync(
+      `${this.repositoryLocation}${sep}${this.name}`,
+      `// change for commit #${i + 1} `
+    );
+  }
+
+  private createFileWithContentInRepository(fileName: string): void {
+    writeFileSync(
+      `${this.repositoryLocation}${sep}${fileName}`,
+      new Array(this.numberOfLinesInFile)
+        .fill(null)
+        .map((value, index) => `console.log(${index});`)
+        .join("\n")
+    );
+  }
+
+  private addFileToRepository(): void {
+    execSync(`git -C ${this.repositoryLocation} add --all`);
+  }
+}