diff --git a/ahk2 b/ahk2
index 5be91832..83dabc48 160000
--- a/ahk2
+++ b/ahk2
@@ -1 +1 @@
-Subproject commit 5be918325917ddc9a3500778c30a55ca5dd4086d
+Subproject commit 83dabc48b4096c9e1d9a7708dddcbbba79ebe7a1
diff --git a/demos/manualTests/definitionProvider/included.ahk1 b/e2e/definitionProvider/included.ahk1
similarity index 86%
rename from demos/manualTests/definitionProvider/included.ahk1
rename to e2e/definitionProvider/included.ahk1
index 3c3cbf77..37d727dc 100644
--- a/demos/manualTests/definitionProvider/included.ahk1
+++ b/e2e/definitionProvider/included.ahk1
@@ -4,6 +4,7 @@ SendMode, Input
 SetBatchLines, -1
 SetWorkingDir, %A_ScriptDir%
 
+; Hi from included.ahk1
 MyDefProviderFunc() {
     MsgBox % "Hi from MyDefProviderFunc"
 }
\ No newline at end of file
diff --git a/demos/manualTests/definitionProvider/main.ahk1 b/e2e/definitionProvider/main.ahk1
similarity index 100%
rename from demos/manualTests/definitionProvider/main.ahk1
rename to e2e/definitionProvider/main.ahk1
diff --git a/src/providers/completionProvider.ts b/src/providers/completionProvider.ts
index 52be6b94..efe2f6d8 100644
--- a/src/providers/completionProvider.ts
+++ b/src/providers/completionProvider.ts
@@ -92,7 +92,7 @@ export const provideCompletionItemsInner = (
 ): vscode.CompletionItem[] =>
     methods
         .map((m) => completionItemsForMethod(m, uriString, lineNumber))
-        .reduce((a, b) => a.concat(b), [])
+        .reduce((a, b) => a.concat(b), []) // reduce from 2D array to 1D array
         .concat(variables.map(completionItemForVariable));
 
 export class CompletionProvider implements vscode.CompletionItemProvider {
diff --git a/src/providers/defProvider.e2e.ts b/src/providers/defProvider.e2e.ts
index 430d8542..0ae685f7 100644
--- a/src/providers/defProvider.e2e.ts
+++ b/src/providers/defProvider.e2e.ts
@@ -1,6 +1,36 @@
 import assert from 'assert';
 import { tryGetFileLink } from './defProvider';
+import path from 'path';
+import {
+    getActiveEditor,
+    getDocument,
+    goToDefinition,
+    goToLine,
+    showDocument,
+    sleep,
+} from '../test/utils';
 
+/** Currently in `/out/src/providers`, want to get to `/` */
+const rootPath = path.join(__dirname, '..', '..', '..');
+
+suite('provideDefinition', () => {
+    test('go to definition', async () => {
+        const filePath = path.resolve(
+            rootPath,
+            `./e2e/definitionProvider/main.ahk1`,
+        );
+        const doc = await getDocument(filePath);
+        const editor = await showDocument(doc);
+        await sleep(1000); // wait for workspace to be indexed
+
+        goToLine(editor, 10);
+
+        await goToDefinition();
+        assert(getActiveEditor().document.fileName.includes('included.ahk1'));
+    });
+});
+
+// Unit test masked as e2e test due to dependency on vscode types
 suite(tryGetFileLink.name, () => {
     const tests: [
         name: string,
diff --git a/src/test/config.e2e.ts b/src/test/config.e2e.ts
index eb9d0136..5bf03c45 100644
--- a/src/test/config.e2e.ts
+++ b/src/test/config.e2e.ts
@@ -11,10 +11,10 @@ import {
     sleep,
     updateConfig,
 } from './utils';
-import { resolve } from 'path';
 import { ConfigKey, LibIncludeType, ShowOutput } from '../common/global';
 import { suite, before, test } from 'mocha';
 
+/** Currently in `/out/src/test`, want to get to `/` */
 const rootPath = path.join(__dirname, '..', '..', '..');
 
 // Currently in `out` folder, need to get back to main `src` folder
@@ -88,7 +88,7 @@ suite('exclude', () => {
             if (version === 1) {
                 await updateConfig<string[]>(ConfigKey.exclude, exclude);
             }
-            const filePath = resolve(rootPath, `./e2e/main.ahk${version}`);
+            const filePath = path.resolve(rootPath, `./e2e/main.ahk${version}`);
             const doc = await getDocument(filePath);
             const editor = await showDocument(doc);
             await sleep(1_000); // todo only these tests are extra flaky
@@ -105,7 +105,7 @@ suite('v2.general.librarySuggestions', () => {
     let editor: vscode.TextEditor;
     before(async () => {
         await updateConfig<string[]>(ConfigKey.exclude, []);
-        const filePath = resolve(rootPath, './e2e/main.ahk2');
+        const filePath = path.resolve(rootPath, './e2e/main.ahk2');
         const doc = await getDocument(filePath);
         editor = await showDocument(doc);
         await sleep(1_000);
diff --git a/src/test/utils.ts b/src/test/utils.ts
index 60cd54b3..00f437b1 100644
--- a/src/test/utils.ts
+++ b/src/test/utils.ts
@@ -53,6 +53,7 @@ export const updateConfig = async <T>(
 /**
  * Adds the provided snippetText at the current selection of the editor
  * and adds a newline to minimize syntax errors.
+ *
  * Waits after selecting so callers don't have to.
  */
 export const addAndSelectSnippet = async (
@@ -80,3 +81,28 @@ export const getCompletionSuggestionLabels = async (
     const labels = completionItems?.items.map((i) => i.label);
     return labels;
 };
+
+export const goToDefinition = async (): Promise<void> => {
+    await vscode.commands.executeCommand('editor.action.revealDefinition');
+};
+
+/**
+ * Move the seleciton to the 1-based line number.
+ *
+ * Optionally provide the 1-based column number: The selection will be placed before this column.
+ * Provide 0 for the start of the line.
+ *
+ * `columnNumber` defaults to 0
+ */
+export const goToLine = (
+    editor: vscode.TextEditor,
+    lineNumber: number,
+    columnNumber: number = 0,
+): void => {
+    const pos = new vscode.Position(lineNumber - 1, columnNumber);
+    editor.selection = new vscode.Selection(pos, pos);
+};
+
+export const getActiveEditor = (): vscode.TextEditor => {
+    return vscode.window.activeTextEditor;
+};