diff --git a/dist/main.js b/dist/main.js
index e20b9568..030a9ba9 100644
--- a/dist/main.js
+++ b/dist/main.js
@@ -22798,7 +22798,13 @@ function createHref(options, file) {
 	const relative = file.file.replace(options.prefix, "");
 	const parts = relative.split("/");
 	const filename = parts[parts.length - 1];
-	const url = path.join(options.repository, 'blob', options.commit, options.workingDir || './', relative);
+	const url = path.join(
+		options.repository,
+		"blob",
+		options.commit || options.defaultBranch,
+		options.workingDir || "./",
+		relative,
+	);
 	return {
 		href: `https://github.com/${url}`,
 		filename
@@ -23047,9 +23053,13 @@ async function getChangedFiles(githubClient, options, context) {
 		);
 	}
 
+	// Normalize the working directory path from './' to '' or './src' to 'src'
+	const workingDir = options.workingDir.replace(/^.\//, "");
+
+	// Return the list of changed files, removing the working directory prefix and starting slash.
 	return response.data.files
 		.filter(file => file.status == "modified" || file.status == "added")
-		.map(file => file.filename)
+		.map(file => file.filename.replace(workingDir, "").replace(/^\//, ""))
 }
 
 const REQUESTED_COMMENTS_PER_PAGE = 20;
@@ -23106,6 +23116,7 @@ async function main$1() {
 		core$1.getInput("filter-changed-files").toLowerCase() === "true";
 	const shouldDeleteOldComments =
 		core$1.getInput("delete-old-comments").toLowerCase() === "true";
+	const defaultBranch = core$1.getInput("default-branch") || "main";
 	const title = core$1.getInput("title");
 
 	const raw = await fs.promises.readFile(lcovFile, "utf-8").catch(err => null);
@@ -23124,6 +23135,7 @@ async function main$1() {
 		repository: github_1.payload.repository.full_name,
 		prefix: normalisePath(`${process.env.GITHUB_WORKSPACE}/`),
 		workingDir,
+		defaultBranch,
 	};
 
 	if (github_1.eventName === "pull_request") {
diff --git a/src/get_changes.js b/src/get_changes.js
index d8f322cb..435d9129 100644
--- a/src/get_changes.js
+++ b/src/get_changes.js
@@ -23,7 +23,11 @@ export async function getChangedFiles(githubClient, options, context) {
 		)
 	}
 
+	// Normalize the working directory path from './' to '' or './src' to 'src'
+	const workingDir = options.workingDir.replace(/^.\//, "")
+
+	// Return the list of changed files, removing the working directory prefix and starting slash.
 	return response.data.files
 		.filter(file => file.status == "modified" || file.status == "added")
-		.map(file => file.filename)
+		.map(file => file.filename.replace(workingDir, "").replace(/^\//, ""))
 }
diff --git a/src/get_changes_test.js b/src/get_changes_test.js
new file mode 100644
index 00000000..54979373
--- /dev/null
+++ b/src/get_changes_test.js
@@ -0,0 +1,116 @@
+import { getChangedFiles } from "./get_changes"
+import * as core from "@actions/core"
+
+jest.mock("@actions/core")
+
+describe("getChangedFiles", () => {
+	let mockGithubClient
+
+	beforeEach(() => {
+		mockGithubClient = {
+			repos: {
+				compareCommits: jest.fn(),
+			},
+		}
+		core.setFailed = jest.fn()
+	})
+
+	it("should fail if commit or baseCommit is missing", async () => {
+		const options = { workingDir: "./" }
+		const context = {
+			eventName: "push",
+			repo: { owner: "owner", repo: "repo" },
+		}
+
+		mockGithubClient.repos.compareCommits.mockResolvedValue({
+			status: 500,
+			data: {
+        files: [],
+      },
+		})
+
+		await getChangedFiles(mockGithubClient, options, context)
+
+		expect(core.setFailed).toHaveBeenCalledWith(
+			"The base and head commits are missing from the payload for this push event.",
+		)
+	})
+
+	it("should fail on non-200 response from GitHub API", async () => {
+		const options = {
+			commit: "headSha",
+			baseCommit: "baseSha",
+			workingDir: "./",
+		}
+		const context = {
+			eventName: "push",
+			repo: { owner: "owner", repo: "repo" },
+		}
+
+		mockGithubClient.repos.compareCommits.mockResolvedValue({
+			status: 404,
+			data: {
+        files: [],
+      },
+		})
+
+		await getChangedFiles(mockGithubClient, options, context)
+
+		expect(core.setFailed).toHaveBeenCalledWith(
+			"The GitHub API for comparing the base and head commits for this push event returned 404, expected 200.",
+		)
+	})
+
+	it("should return a list of modified and added files", async () => {
+		const options = {
+			commit: "headSha",
+			baseCommit: "baseSha",
+			workingDir: "./src",
+		}
+		const context = {
+			eventName: "push",
+			repo: { owner: "owner", repo: "repo" },
+		}
+
+		mockGithubClient.repos.compareCommits.mockResolvedValue({
+			status: 200,
+			data: {
+				files: [
+					{ status: "modified", filename: "src/file1.js" },
+					{ status: "added", filename: "src/file2.js" },
+					{ status: "removed", filename: "src/file3.js" },
+				],
+			},
+		})
+
+		const result = await getChangedFiles(mockGithubClient, options, context)
+
+		expect(result).toEqual(["file1.js", "file2.js"])
+	})
+
+	it("should correctly normalize working directory", async () => {
+		const options = {
+			commit: "headSha",
+			baseCommit: "baseSha",
+			workingDir: "./",
+		}
+		const context = {
+			eventName: "push",
+			repo: { owner: "owner", repo: "repo" },
+		}
+
+		mockGithubClient.repos.compareCommits.mockResolvedValue({
+			status: 200,
+			data: {
+				files: [
+					{ status: "modified", filename: "/file1.js" },
+					{ status: "added", filename: "/file2.js" },
+				],
+			},
+		})
+
+		const result = await getChangedFiles(mockGithubClient, options, context)
+
+		expect(result).toEqual(["file1.js", "file2.js"])
+	})
+})
diff --git a/src/index.js b/src/index.js
index 2efc5fb0..bdd018f5 100644
--- a/src/index.js
+++ b/src/index.js
@@ -21,6 +21,7 @@ async function main() {
 		core.getInput("filter-changed-files").toLowerCase() === "true"
 	const shouldDeleteOldComments =
 		core.getInput("delete-old-comments").toLowerCase() === "true"
+	const defaultBranch = core.getInput("default-branch") || "main"
 	const title = core.getInput("title")
 
 	const raw = await fs.readFile(lcovFile, "utf-8").catch(err => null)
@@ -39,6 +40,7 @@ async function main() {
 		repository: context.payload.repository.full_name,
 		prefix: normalisePath(`${process.env.GITHUB_WORKSPACE}/`),
 		workingDir,
+		defaultBranch,
 	}
 
 	if (context.eventName === "pull_request") {
diff --git a/src/util.js b/src/util.js
index 71a319f6..1f05fd62 100644
--- a/src/util.js
+++ b/src/util.js
@@ -8,7 +8,13 @@ export function createHref(options, file) {
 	const relative = file.file.replace(options.prefix, "")
 	const parts = relative.split("/")
 	const filename = parts[parts.length - 1]
-	const url = path.join(options.repository, 'blob', options.commit, options.workingDir || './', relative)
+	const url = path.join(
+		options.repository,
+		"blob",
+		options.commit || options.defaultBranch,
+		options.workingDir || "./",
+		relative,
+	)
 	return {
 		href: `https://github.com/${url}`,
 		filename