test: add image URL "homebrew-img" source check

README.md

@@ -37,6 +37,7 @@ There are a few conventions used which should be followed when creating homebrew
  - Use `https://github.com/TheGiddyLimit/homebrew` as the source URL for sources without one.
  - Only include content authors in the source `"author"` field; conversion credit should be given in a `"convertedBy"` field (with the same format).
  - Include a `"dateAdded"` property in file metadata, which is a Unix timestamp (in seconds) at which the file was added. See [here](https://github.com/TheGiddyLimit/homebrew/blob/master/spell/Sample%20-%20Giddy%3B%20Assorted%20Marginalia.json#L29) for an example of the structure; an example timestamp would be `1537874753`. You can view and copy the current Unix time [here](https://www.epochconverter.com/).
+ - Images (and similar assets, e.g. character sheet PDFs) should be added to the [homebrew image repository](https://github.com/TheGiddyLimit/homebrew-img)
 
 #### Useful links
 

_test/test-tags.js → _test/test-file-contents.js

@@ -1,6 +1,7 @@
+import fs from "fs";
 import {DataTester, BraceCheck, EscapeCharacterCheck} from "5etools-utils";
 import * as Uf from "5etools-utils/lib/UtilFs.js";
-import fs from "fs";
+import {ImageUrlCheck} from "./test-file-contents/ImageUrlCheck.js";
 
 const TIME_TAG = "\tRun duration";
 console.time(TIME_TAG);
@@ -9,6 +10,7 @@ async function main () {
 	const ClazzDataTesters = [
 		BraceCheck,
 		EscapeCharacterCheck,
+		ImageUrlCheck,
 	];
 	DataTester.register({ClazzDataTesters});
 

_test/test-file-contents/ImageUrlCheck.js

@@ -0,0 +1,53 @@
+import {DataTesterBase} from "5etools-utils/lib/TestData.js";
+import {ObjectWalker} from "5etools-utils/lib/ObjectWalker.js";
+
+export class ImageUrlCheck extends DataTesterBase {
+	static _URL_PREFIX_HOMEBREW_IMG = `https://raw.githubusercontent.com/TheGiddyLimit/homebrew-img/main/`;
+	static _RE_HOMEBREW_IMG_PATH = /^(?<type>img|pdf)\/(?<source>[^/]+)\//;
+
+	static registerParsedFileCheckers (parsedJsonChecker) {
+		parsedJsonChecker.registerFileHandler(this);
+	}
+
+	static handleFile (file, contents) {
+		const checker = new this({contents});
+
+		checker._walk({file, contents});
+	}
+
+	constructor ({contents}) {
+		super();
+		this._sources = new Set(
+			(contents._meta?.sources?.map(src => src?.json) || [])
+				.filter(Boolean),
+		);
+	}
+
+	_walk ({file, contents}) {
+		ObjectWalker.walk({
+			obj: contents,
+			filePath: file,
+			primitiveHandlers: {
+				object: this._checkObject.bind(this),
+			},
+		});
+	}
+
+	_checkObject (obj, {filePath}) {
+		if (obj.type !== "image" || obj.href?.type !== "external" || !obj.href?.url) return;
+
+		const {url} = obj.href;
+		if (!url.toLowerCase().startsWith(this.constructor._URL_PREFIX_HOMEBREW_IMG.toLowerCase())) return;
+
+		const mPath = this.constructor._RE_HOMEBREW_IMG_PATH.exec(url.slice(this.constructor._URL_PREFIX_HOMEBREW_IMG.length));
+		if (!mPath) {
+			this.constructor._addMessage(`Unknown "homebrew-img" URL pattern in file "${filePath}": "${url}"\n`);
+			return;
+		}
+
+		const {source, type} = mPath.groups;
+		if (this._sources.has(source)) return;
+
+		this.constructor._addMessage(`Image source part "${source}" in "homebrew-img" ${type} URL did not match sources found in file "_meta" in file "${filePath}": "${url}"\n`);
+	}
+}

package.json

@@ -11,10 +11,10 @@
 		"build:clean:base": "node _node/clean-and-test.js",
 		"build:clean:html": "node _node/clean-html.js",
 		"test:json": "test-json-brew",
-		"test:tags": "node _test/test-tags.js",
+		"test:file-contents": "node _test/test-file-contents.js",
 		"test:file-locations": "test-file-locations",
 		"test:file-extensions": "test-file-extensions",
-		"test": "npm run build:clean && npm run build:index && npm run test:json && npm run test:file-locations && npm run test:file-extensions && npm run test:tags"
+		"test": "npm run build:clean && npm run build:index && npm run test:json && npm run test:file-locations && npm run test:file-extensions && npm run test:file-contents"
 	},
 	"repository": {
 		"type": "git",