private File doCreateExternalExtensionInFolder(File externalFolder, String extensionName,
			String nameProperty, String version) throws Exception {
		ResourceFile root = new ResourceFile(new ResourceFile(externalFolder), extensionName);
		root.mkdir();

		// Have to add a prop file so this will be recognized as an extension
		File propFile = new ResourceFile(root, "extension.properties").getFile(false);
		assertTrue(propFile.createNewFile());
		Properties props = new Properties();
		props.put("name", nameProperty);
		props.put("description", "This is a description for " + extensionName);
		props.put("author", "First Last");
		props.put("createdOn", new SimpleDateFormat("MM/dd/yyyy").format(new Date()));
		props.put("version", version);

		try (OutputStream os = new FileOutputStream(propFile)) {
			props.store(os, null);
		}

		File manifest = new ResourceFile(root, ModuleUtilities.MANIFEST_FILE_NAME).getFile(false);
		manifest.createNewFile();

		return root.getFile(false);
	}
Tests for the {@link ExtensionInstaller} class.
Ghidra/Framework/Project/src/test/java/ghidra/framework/project/extensions/ExtensionInstallerTest.java