diff --git a/test/config.spec.ts b/test/config.spec.ts
index 4cfb9ef..f0bb4de 100644
--- a/test/config.spec.ts
+++ b/test/config.spec.ts
@@ -20,7 +20,7 @@ describe('Config Tests', () => {
   })
 
   it('config.filter works', () => {
-    let template = 'My favorite food is <%= it.fav %>'
+    const template = 'My favorite food is <%= it.fav %>'
 
     expect(render(template, {})).toEqual('My favorite food is undefined')
 
diff --git a/test/file-handlers.spec.ts b/test/file-handlers.spec.ts
index 7867c93..fc22d69 100644
--- a/test/file-handlers.spec.ts
+++ b/test/file-handlers.spec.ts
@@ -91,7 +91,7 @@ describe('Simple renderFile tests', () => {
 
 describe('File location tests', () => {
   it('locates a file with the views option', async () => {
-    let res = await renderFile(
+    const res = await renderFile(
       'simple.eta',
       { name: 'Ada' },
       { views: path.join(__dirname, 'templates') }
diff --git a/test/file-utils.spec.ts b/test/file-utils.spec.ts
index 7603d76..50087d0 100644
--- a/test/file-utils.spec.ts
+++ b/test/file-utils.spec.ts
@@ -19,9 +19,9 @@ describe('Filepath caching', () => {
     // This test renders templates/has-include.eta with caching enabled, then checks to make sure
     // `config.filepathCache` contains the expected result afterward
 
-    let viewsDir = path.join(__dirname, 'templates')
+    const viewsDir = path.join(__dirname, 'templates')
 
-    let templateResult = await renderFile('has-include', {}, { views: viewsDir, cache: true })
+    const templateResult = await renderFile('has-include', {}, { views: viewsDir, cache: true })
 
     expect(templateResult).toEqual(
       `This is the outermost template. Now we'll include a partial
@@ -36,11 +36,11 @@ Hi Test Runner`
     // Filepath caching is based on the premise that given the same path, includer filename, root directory, and views directory (or directories)
     // the getPath function will always return the same result (assuming that caching is enabled and we're not expecting the templates to change)
 
-    let pathToHasInclude = `{"filename":"${viewsDir}/has-include.eta","path":"./partial","views":"${viewsDir}"}`
+    const pathToHasInclude = `{"filename":"${viewsDir}/has-include.eta","path":"./partial","views":"${viewsDir}"}`
 
-    let pathToPartial = `{"filename":"${viewsDir}/partial.eta","path":"./simple","views":"${viewsDir}"}`
+    const pathToPartial = `{"filename":"${viewsDir}/partial.eta","path":"./simple","views":"${viewsDir}"}`
 
-    let pathToSimple = `{"path":"has-include","views":"${viewsDir}"}`
+    const pathToSimple = `{"path":"has-include","views":"${viewsDir}"}`
 
     expect(config.filepathCache).toEqual({
       [pathToHasInclude]: `${viewsDir}/partial.eta`,
diff --git a/test/render.spec.ts b/test/render.spec.ts
index f6a2a2e..08e2da2 100644
--- a/test/render.spec.ts
+++ b/test/render.spec.ts
@@ -21,7 +21,7 @@ describe('Simple Render checks', () => {
     })
     it('Rendering function works', async () => {
       const template = 'Hello <%= await it.getName() %>!'
-      let getName = () => {
+      const getName = () => {
         return new Promise((res) => {
           setTimeout(() => {
             res('Ada')
@@ -32,7 +32,7 @@ describe('Simple Render checks', () => {
     })
     it('Rendering async function works', async () => {
       const template = 'Hello <%= await it.getName() %>!'
-      let getName = () => {
+      const getName = () => {
         return new Promise((res) => {
           setTimeout(() => {
             res('Ada')
@@ -67,15 +67,15 @@ describe('Renders with different scopes', () => {
 
 describe('processTemplate plugin', () => {
   it('Simple plugin works correctly', () => {
-    let template = ':thumbsup:'
+    const template = ':thumbsup:'
 
-    let emojiTransform = {
+    const emojiTransform = {
       processTemplate: function (str: string) {
         return str.replace(':thumbsup:', '👍')
       }
     }
 
-    let res = render(
+    const res = render(
       template,
       {},
       {
@@ -87,27 +87,27 @@ describe('processTemplate plugin', () => {
   })
 
   it('Multiple chained plugins work correctly', () => {
-    let template = ':thumbsup: This is a cool template'
+    const template = ':thumbsup: This is a cool template'
 
-    let emojiTransform = {
+    const emojiTransform = {
       processTemplate: function (str: string) {
         return str.replace(':thumbsup:', '👍')
       }
     }
 
-    let capitalizeCool = {
+    const capitalizeCool = {
       processTemplate: function (str: string) {
         return str.replace('cool', 'COOL')
       }
     }
 
-    let replaceThumbsUp = {
+    const replaceThumbsUp = {
       processTemplate: function (str: string) {
         return str.replace('👍', '✨')
       }
     }
 
-    let res = render(
+    const res = render(
       template,
       {},
       {