diff --git a/server/frontend/src/components/Bugs/PublicationForm.vue b/server/frontend/src/components/Bugs/PublicationForm.vue
index f351d347..4997d77d 100644
--- a/server/frontend/src/components/Bugs/PublicationForm.vue
+++ b/server/frontend/src/components/Bugs/PublicationForm.vue
@@ -710,7 +710,7 @@ import * as api from "../../api";
 import mime from "mime";
 import * as bugzillaApi from "../../bugzilla_api";
 import * as HandlebarsHelpers from "../../handlebars_helpers";
-import { errorParser } from "../../helpers";
+import { errorParser, parseFilename, buildFilename } from "../../helpers";
 import CrashDataSection from "./CrashDataSection.vue";
 import FullPPCSelect from "./FullPPCSelect.vue";
 import HelpPopover from "./HelpPopover.vue";
@@ -821,30 +821,17 @@ export default defineComponent({
     });
 
     const filenameWithExtension = computed(() => {
-      return `${fileName.value}.${fileExtension.value}`;
+      return buildFilename(fileName.value, fileExtension.value);
     });
 
     watch([entry, template], () => {
       if (entry.value) {
-        // Extract the original testcase path and get the extension
-        const originalTestcasePath = entry.value.testcase.split("/");
-        const originalFilename =
-          originalTestcasePath[originalTestcasePath.length - 1];
-        const originalParts = originalFilename.split(".");
-        const originalExtension = originalParts[originalParts.length - 1];
-
-        // If template has a testcase_filename, extract just the base name (without extension)
-        if (template.value?.testcase_filename) {
-          const templateParts = template.value.testcase_filename.split(".");
-          // If the template filename has an extension, remove it to get just the base name
-          fileName.value =
-            templateParts.slice(0, -1).join(".") || templateParts[0];
-        } else {
-          // Use the original filename without extension
-          fileName.value = originalParts.slice(0, -1).join(".");
-        }
-
-        fileExtension.value = originalExtension;
+        const { basename, extension } = parseFilename(
+          entry.value.testcase,
+          template.value?.testcase_filename,
+        );
+        fileName.value = basename;
+        fileExtension.value = extension;
       }
     });
 
diff --git a/server/frontend/src/helpers.js b/server/frontend/src/helpers.js
index 0bcba837..6d5d10bc 100644
--- a/server/frontend/src/helpers.js
+++ b/server/frontend/src/helpers.js
@@ -220,3 +220,45 @@ export function formatMonthly(d) {
   const date = new Date(d);
   return `${months[date.getMonth()]} ${date.getFullYear()}`;
 }
+
+/**
+ * Parse a testcase file path into basename and extension
+ * @param {string} testcasePath - Full path to the testcase file (e.g. "/path/to/test.txt")
+ * @param {string|null} templateFilename - Optional template filename to use instead of original
+ * @returns {{basename: string, extension: string|null}} Object with basename and extension
+ */
+export function parseFilename(testcasePath, templateFilename = null) {
+  const pathParts = testcasePath.split("/");
+  const originalFilename = pathParts[pathParts.length - 1];
+  const originalParts = originalFilename.split(".");
+
+  const hasExtension = originalParts.length > 1;
+  const extension = hasExtension
+    ? originalParts[originalParts.length - 1]
+    : null;
+
+  let basename;
+  if (templateFilename) {
+    const templateParts = templateFilename.split(".");
+    basename =
+      templateParts.length > 1
+        ? templateParts.slice(0, -1).join(".")
+        : templateParts[0];
+  } else {
+    basename = hasExtension
+      ? originalParts.slice(0, -1).join(".")
+      : originalParts[0];
+  }
+
+  return { basename, extension };
+}
+
+/**
+ * Build a filename from basename and extension
+ * @param {string} basename - The base filename without extension
+ * @param {string|null} extension - Optional file extension (without dot)
+ * @returns {string} Complete filename with extension if provided
+ */
+export function buildFilename(basename, extension) {
+  return extension ? `${basename}.${extension}` : basename;
+}
diff --git a/server/frontend/tests/helpers.test.js b/server/frontend/tests/helpers.test.js
new file mode 100644
index 00000000..3a455117
--- /dev/null
+++ b/server/frontend/tests/helpers.test.js
@@ -0,0 +1,58 @@
+import { parseFilename, buildFilename } from "../src/helpers";
+
+describe("parseFilename", () => {
+  test.each([
+    [
+      "testcase with file extension",
+      "tests/test.txt",
+      "testcase.zip",
+      { basename: "testcase", extension: "txt" },
+    ],
+    [
+      "testcase without an extension",
+      "tests/original",
+      "template_name.html",
+      { basename: "template_name", extension: null },
+    ],
+    [
+      "testcase with no basename",
+      "test/.bin",
+      null,
+      { basename: "", extension: "bin" },
+    ],
+    [
+      "testcase with an extension (no template)",
+      "tests/test.txt",
+      null,
+      { basename: "test", extension: "txt" },
+    ],
+    [
+      "testcase without an extension (no template)",
+      "tests/test",
+      null,
+      { basename: "test", extension: null },
+    ],
+    [
+      "testcase with multiple dots (no template)",
+      "test/test.min.js",
+      null,
+      { basename: "test.min", extension: "js" },
+    ],
+  ])("%s", (_description, testcasePath, templateFilename, expected) => {
+    const result = parseFilename(testcasePath, templateFilename);
+    expect(result).toEqual(expected);
+  });
+});
+
+describe("buildFilename", () => {
+  test.each([
+    ["testcase with an extension", "test", "txt", "test.txt"],
+    ["testcase without an extension", "test", null, "test"],
+    ["testcase with an empty extension", "test", "", "test"],
+    ["testcase with multiple dots", "test.min", "js", "test.min.js"],
+    ["testcase with an empty basename", "", "bin", ".bin"],
+  ])("%s", (_description, basename, extension, expected) => {
+    const result = buildFilename(basename, extension);
+    expect(result).toBe(expected);
+  });
+});