diff --git a/src/app/PageLayout.tsx b/src/app/PageLayout.tsx
index 6f4bd8a..83c8118 100644
--- a/src/app/PageLayout.tsx
+++ b/src/app/PageLayout.tsx
@@ -18,8 +18,8 @@ export function PageLayout({ children }: { children: ReactNode }) {
   };
 
   return (
-    <div className="min-h-screen bg-background">
-      <div className="grid-pattern" />
+    <div className="min-h-screen bg-background" data-testid="page-layout">
+      <div className="grid-pattern" aria-hidden="true" />
 
       <NavigationSidebar />
 
@@ -29,7 +29,7 @@ export function PageLayout({ children }: { children: ReactNode }) {
         transition={{ type: 'spring', damping: 30, stiffness: 300 }}
         className="relative z-10 flex flex-col min-h-screen"
       >
-        <header className="border-b border-border bg-background/95 backdrop-blur-md sticky top-0 z-20 overflow-hidden">
+        <header className="border-b border-border bg-background/95 backdrop-blur-md sticky top-0 z-20 overflow-hidden" data-testid="page-header">
           <div
             className="container mx-auto px-2 py-3 sm:px-6 sm:py-6 w-full min-w-0"
             style={{
@@ -48,7 +48,7 @@ export function PageLayout({ children }: { children: ReactNode }) {
                 <div className="logo-icon-box">
                   <Code weight="bold" />
                 </div>
-                <span className="logo-text" aria-label="CodeSnippet">
+                <span className="logo-text" aria-label="CodeSnippet" data-testid="logo-text">
                   CodeSnippet
                 </span>
               </motion.div>
@@ -66,6 +66,7 @@ export function PageLayout({ children }: { children: ReactNode }) {
         <main
           className="container mx-auto px-3 py-4 sm:px-6 sm:py-8 flex-1"
           style={safeAreaPadding}
+          data-testid="main-content"
         >
           <div className="mb-4">
             <AppStatusAlerts />
diff --git a/src/components/SnippetManagerRedux.tsx b/src/components/SnippetManagerRedux.tsx
index aa2827d..aeb1ba2 100644
--- a/src/components/SnippetManagerRedux.tsx
+++ b/src/components/SnippetManagerRedux.tsx
@@ -45,7 +45,7 @@ export function SnippetManagerRedux() {
 
   if (loading) {
     return (
-      <div className="text-center py-20">
+      <div className="text-center py-20" data-testid="snippet-manager-loading">
         <p className="text-muted-foreground">Loading snippets...</p>
       </div>
     )
@@ -75,7 +75,7 @@ export function SnippetManagerRedux() {
   }
 
   return (
-    <div className="space-y-6">
+    <div className="space-y-6" data-testid="snippet-manager">
       <NamespaceSelector
         selectedNamespaceId={selectedNamespaceId}
         onNamespaceChange={handleNamespaceChange}
diff --git a/src/components/features/namespace-manager/CreateNamespaceDialog.tsx b/src/components/features/namespace-manager/CreateNamespaceDialog.tsx
index 6f27696..a5f769d 100644
--- a/src/components/features/namespace-manager/CreateNamespaceDialog.tsx
+++ b/src/components/features/namespace-manager/CreateNamespaceDialog.tsx
@@ -33,11 +33,16 @@ export function CreateNamespaceDialog({
   return (
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogTrigger asChild>
-        <Button variant="outline" size="icon">
-          <Plus weight="bold" />
+        <Button
+          variant="outline"
+          size="icon"
+          data-testid="create-namespace-trigger"
+          aria-label="Create new namespace"
+        >
+          <Plus weight="bold" aria-hidden="true" />
         </Button>
       </DialogTrigger>
-      <DialogContent>
+      <DialogContent data-testid="create-namespace-dialog">
         <DialogHeader>
           <DialogTitle>Create Namespace</DialogTitle>
           <DialogDescription>
@@ -50,13 +55,23 @@ export function CreateNamespaceDialog({
             value={namespaceName}
             onChange={(e) => onNamespaceNameChange(e.target.value)}
             onKeyPress={(e) => e.key === 'Enter' && onCreateNamespace()}
+            data-testid="namespace-name-input"
+            aria-label="Namespace name"
           />
         </div>
         <DialogFooter>
-          <Button variant="outline" onClick={() => onOpenChange(false)}>
+          <Button
+            variant="outline"
+            onClick={() => onOpenChange(false)}
+            data-testid="create-namespace-cancel-btn"
+          >
             Cancel
           </Button>
-          <Button onClick={onCreateNamespace} disabled={loading}>
+          <Button
+            onClick={onCreateNamespace}
+            disabled={loading}
+            data-testid="create-namespace-save-btn"
+          >
             Create
           </Button>
         </DialogFooter>
diff --git a/src/components/features/namespace-manager/DeleteNamespaceDialog.tsx b/src/components/features/namespace-manager/DeleteNamespaceDialog.tsx
index adcd495..3e56a8a 100644
--- a/src/components/features/namespace-manager/DeleteNamespaceDialog.tsx
+++ b/src/components/features/namespace-manager/DeleteNamespaceDialog.tsx
@@ -38,13 +38,15 @@ export function DeleteNamespaceDialog({
           variant="outline"
           size="icon"
           onClick={onOpenDialog}
+          data-testid="delete-namespace-trigger"
+          aria-label="Delete namespace"
         >
-          <Trash weight="bold" />
+          <Trash weight="bold" aria-hidden="true" />
         </Button>
       )}
 
       <AlertDialog open={open} onOpenChange={onOpenChange}>
-        <AlertDialogContent>
+        <AlertDialogContent data-testid="delete-namespace-dialog">
           <AlertDialogHeader>
             <AlertDialogTitle>Delete Namespace</AlertDialogTitle>
             <AlertDialogDescription>
@@ -52,8 +54,14 @@ export function DeleteNamespaceDialog({
             </AlertDialogDescription>
           </AlertDialogHeader>
           <AlertDialogFooter>
-            <AlertDialogCancel>Cancel</AlertDialogCancel>
-            <AlertDialogAction onClick={onDeleteNamespace} disabled={loading}>
+            <AlertDialogCancel data-testid="delete-namespace-cancel-btn">
+              Cancel
+            </AlertDialogCancel>
+            <AlertDialogAction
+              onClick={onDeleteNamespace}
+              disabled={loading}
+              data-testid="delete-namespace-confirm-btn"
+            >
               Delete
             </AlertDialogAction>
           </AlertDialogFooter>
diff --git a/src/components/features/namespace-manager/NamespaceSelector.tsx b/src/components/features/namespace-manager/NamespaceSelector.tsx
index 4425442..9750ab9 100644
--- a/src/components/features/namespace-manager/NamespaceSelector.tsx
+++ b/src/components/features/namespace-manager/NamespaceSelector.tsx
@@ -109,22 +109,30 @@ export function NamespaceSelector({ selectedNamespaceId, onNamespaceChange }: Na
   return (
     <div className="flex items-center gap-2">
       <div className="flex items-center gap-2 text-muted-foreground">
-        <Folder weight="fill" className="h-4 w-4" />
+        <Folder weight="fill" className="h-4 w-4" aria-hidden="true" />
         <span className="text-sm font-medium">Namespace:</span>
       </div>
-      
+
       <Select
         value={selectedNamespaceId || undefined}
         onValueChange={onNamespaceChange}
       >
-        <SelectTrigger className="w-[200px]">
+        <SelectTrigger
+          className="w-[200px]"
+          data-testid="namespace-selector-trigger"
+          aria-label="Select namespace"
+        >
           <SelectValue placeholder="Select namespace">
             {selectedNamespace?.name || 'Select namespace'}
           </SelectValue>
         </SelectTrigger>
-        <SelectContent>
+        <SelectContent data-testid="namespace-selector-content">
           {namespaces.map(namespace => (
-            <SelectItem key={namespace.id} value={namespace.id}>
+            <SelectItem
+              key={namespace.id}
+              value={namespace.id}
+              data-testid={`namespace-option-${namespace.id}`}
+            >
               <div className="flex items-center gap-2">
                 <span>{namespace.name}</span>
                 {namespace.isDefault && (
diff --git a/src/components/features/snippet-display/SnippetCardActions.tsx b/src/components/features/snippet-display/SnippetCardActions.tsx
index 64cb853..9048a35 100644
--- a/src/components/features/snippet-display/SnippetCardActions.tsx
+++ b/src/components/features/snippet-display/SnippetCardActions.tsx
@@ -85,8 +85,11 @@ export function SnippetCardActions({
           </DropdownMenuTrigger>
           <DropdownMenuContent align="end" onClick={(e) => e.stopPropagation()}>
             <DropdownMenuSub>
-              <DropdownMenuSubTrigger disabled={isMoving || availableNamespaces.length === 0}>
-                <FolderOpen className="h-4 w-4 mr-2" />
+              <DropdownMenuSubTrigger
+                disabled={isMoving || availableNamespaces.length === 0}
+                data-testid="snippet-card-move-submenu"
+              >
+                <FolderOpen className="h-4 w-4 mr-2" aria-hidden="true" />
                 <span>Move to...</span>
               </DropdownMenuSubTrigger>
               <DropdownMenuSubContent>
@@ -99,6 +102,7 @@ export function SnippetCardActions({
                     <DropdownMenuItem
                       key={namespace.id}
                       onClick={() => onMoveToNamespace(namespace.id)}
+                      data-testid={`move-to-namespace-${namespace.id}`}
                     >
                       {namespace.name}
                       {namespace.isDefault && (
@@ -113,8 +117,9 @@ export function SnippetCardActions({
             <DropdownMenuItem
               onClick={onDelete}
               className="text-destructive focus:text-destructive"
+              data-testid="snippet-card-delete-btn"
             >
-              <Trash className="h-4 w-4 mr-2" />
+              <Trash className="h-4 w-4 mr-2" aria-hidden="true" />
               Delete
             </DropdownMenuItem>
           </DropdownMenuContent>
diff --git a/src/components/features/snippet-editor/InputParameterItem.tsx b/src/components/features/snippet-editor/InputParameterItem.tsx
index 2ffcc91..7879db1 100644
--- a/src/components/features/snippet-editor/InputParameterItem.tsx
+++ b/src/components/features/snippet-editor/InputParameterItem.tsx
@@ -52,6 +52,8 @@ export function InputParameterItem({ param, index, onUpdate, onRemove }: InputPa
                 value={param.name}
                 onChange={(e) => onUpdate(index, 'name', e.target.value)}
                 className="h-8 text-sm"
+                data-testid={`param-name-input-${index}`}
+                aria-label="Parameter name"
               />
             </div>
             <div className="space-y-1.5">
@@ -62,15 +64,20 @@ export function InputParameterItem({ param, index, onUpdate, onRemove }: InputPa
                 value={param.type}
                 onValueChange={(value) => onUpdate(index, 'type', value)}
               >
-                <SelectTrigger id={`param-type-${index}`} className="h-8 text-sm">
+                <SelectTrigger
+                  id={`param-type-${index}`}
+                  className="h-8 text-sm"
+                  data-testid={`param-type-select-${index}`}
+                  aria-label="Parameter type"
+                >
                   <SelectValue />
                 </SelectTrigger>
-                <SelectContent>
-                  <SelectItem value="string">string</SelectItem>
-                  <SelectItem value="number">number</SelectItem>
-                  <SelectItem value="boolean">boolean</SelectItem>
-                  <SelectItem value="array">array</SelectItem>
-                  <SelectItem value="object">object</SelectItem>
+                <SelectContent data-testid={`param-type-options-${index}`}>
+                  <SelectItem value="string" data-testid="type-string">string</SelectItem>
+                  <SelectItem value="number" data-testid="type-number">number</SelectItem>
+                  <SelectItem value="boolean" data-testid="type-boolean">boolean</SelectItem>
+                  <SelectItem value="array" data-testid="type-array">array</SelectItem>
+                  <SelectItem value="object" data-testid="type-object">object</SelectItem>
                 </SelectContent>
               </Select>
             </div>
@@ -80,8 +87,10 @@ export function InputParameterItem({ param, index, onUpdate, onRemove }: InputPa
             size="sm"
             onClick={() => onRemove(index)}
             className="h-8 w-8 p-0 mt-6 text-destructive hover:text-destructive"
+            data-testid={`remove-parameter-btn-${index}`}
+            aria-label={`Remove parameter ${index + 1}`}
           >
-            <Trash className="h-4 w-4" />
+            <Trash className="h-4 w-4" aria-hidden="true" />
           </Button>
         </div>
         <div className="space-y-1.5">
@@ -94,6 +103,8 @@ export function InputParameterItem({ param, index, onUpdate, onRemove }: InputPa
             value={param.defaultValue}
             onChange={(e) => onUpdate(index, 'defaultValue', e.target.value)}
             className="h-8 text-sm font-mono"
+            data-testid={`param-default-input-${index}`}
+            aria-label="Default parameter value"
           />
         </div>
         <div className="space-y-1.5">
@@ -106,6 +117,8 @@ export function InputParameterItem({ param, index, onUpdate, onRemove }: InputPa
             value={param.description || ''}
             onChange={(e) => onUpdate(index, 'description', e.target.value)}
             className="h-8 text-sm"
+            data-testid={`param-description-input-${index}`}
+            aria-label="Parameter description"
           />
         </div>
       </CardContent>
diff --git a/src/components/features/snippet-editor/InputParameterList.tsx b/src/components/features/snippet-editor/InputParameterList.tsx
index ad50a90..6978a6d 100644
--- a/src/components/features/snippet-editor/InputParameterList.tsx
+++ b/src/components/features/snippet-editor/InputParameterList.tsx
@@ -33,8 +33,10 @@ export function InputParameterList({
             size="sm"
             onClick={onAddParameter}
             className="gap-2"
+            data-testid="add-parameter-btn"
+            aria-label="Add new parameter"
           >
-            <Plus className="h-3 w-3" />
+            <Plus className="h-3 w-3" aria-hidden="true" />
             Add Parameter
           </Button>
         </CardTitle>
@@ -50,8 +52,11 @@ export function InputParameterList({
             value={functionName}
             onChange={(e) => onFunctionNameChange(e.target.value)}
             className="bg-background"
+            data-testid="function-name-input"
+            aria-label="Function or component name"
+            aria-describedby="function-name-help"
           />
-          <p className="text-xs text-muted-foreground">
+          <p className="text-xs text-muted-foreground" id="function-name-help">
             The name of the function or component to render. Leave empty to use the default export.
           </p>
         </div>
diff --git a/src/components/features/snippet-editor/SnippetFormFields.tsx b/src/components/features/snippet-editor/SnippetFormFields.tsx
index 52de0e9..4420b60 100644
--- a/src/components/features/snippet-editor/SnippetFormFields.tsx
+++ b/src/components/features/snippet-editor/SnippetFormFields.tsx
@@ -39,19 +39,30 @@ export function SnippetFormFields({
           value={title}
           onChange={(e) => onTitleChange(e.target.value)}
           className={errors.title ? 'border-destructive ring-destructive' : ''}
+          data-testid="snippet-title-input"
+          aria-invalid={!!errors.title}
+          aria-describedby={errors.title ? "title-error" : undefined}
         />
-        {errors.title && <p className="text-sm text-destructive">{errors.title}</p>}
+        {errors.title && (
+          <p className="text-sm text-destructive" id="title-error">
+            {errors.title}
+          </p>
+        )}
       </div>
 
       <div className="space-y-2">
         <Label htmlFor="language">Language</Label>
         <Select value={language} onValueChange={onLanguageChange}>
-          <SelectTrigger id="language">
+          <SelectTrigger
+            id="language"
+            data-testid="snippet-language-select"
+            aria-label="Select programming language"
+          >
             <SelectValue />
           </SelectTrigger>
-          <SelectContent>
+          <SelectContent data-testid="snippet-language-options">
             {LANGUAGES.map((lang) => (
-              <SelectItem key={lang} value={lang}>
+              <SelectItem key={lang} value={lang} data-testid={`language-option-${lang}`}>
                 {lang}
               </SelectItem>
             ))}
@@ -67,6 +78,8 @@ export function SnippetFormFields({
           value={description}
           onChange={(e) => onDescriptionChange(e.target.value)}
           rows={2}
+          data-testid="snippet-description-textarea"
+          aria-label="Snippet description"
         />
       </div>
     </>
diff --git a/src/components/layout/navigation/Navigation.tsx b/src/components/layout/navigation/Navigation.tsx
index 7ebe301..9a3a9aa 100644
--- a/src/components/layout/navigation/Navigation.tsx
+++ b/src/components/layout/navigation/Navigation.tsx
@@ -10,8 +10,11 @@ export function Navigation() {
       className="nav-burger-btn"
       onClick={() => setMenuOpen(!menuOpen)}
       aria-label="Toggle navigation menu"
+      aria-expanded={menuOpen}
+      aria-controls="navigation-sidebar"
+      data-testid="navigation-toggle-btn"
     >
-      <List weight="bold" />
+      <List weight="bold" aria-hidden="true" />
     </button>
   )
 }
diff --git a/src/components/layout/navigation/NavigationSidebar.tsx b/src/components/layout/navigation/NavigationSidebar.tsx
index c5a1a6d..d3b2209 100644
--- a/src/components/layout/navigation/NavigationSidebar.tsx
+++ b/src/components/layout/navigation/NavigationSidebar.tsx
@@ -55,6 +55,9 @@ export function NavigationSidebar() {
               "shadow-xl"
             )}
             data-testid="navigation-sidebar"
+            id="navigation-sidebar"
+            role="navigation"
+            aria-label="Main navigation menu"
           >
             {/* Header */}
             <div className="flex items-center justify-between h-16 px-4 border-b border-border/50">
diff --git a/src/components/snippet-manager/SnippetGrid.tsx b/src/components/snippet-manager/SnippetGrid.tsx
index 4990ca5..0407e7d 100644
--- a/src/components/snippet-manager/SnippetGrid.tsx
+++ b/src/components/snippet-manager/SnippetGrid.tsx
@@ -25,7 +25,12 @@ export function SnippetGrid({
   onToggleSelect,
 }: SnippetGridProps) {
   return (
-    <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
+    <div
+      className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6"
+      data-testid="snippet-grid"
+      role="region"
+      aria-label="Snippets list"
+    >
       {snippets.map((snippet) => (
         <SnippetCard
           key={snippet.id}
diff --git a/src/components/snippet-manager/SnippetToolbar.tsx b/src/components/snippet-manager/SnippetToolbar.tsx
index 188bc6c..f8230ac 100644
--- a/src/components/snippet-manager/SnippetToolbar.tsx
+++ b/src/components/snippet-manager/SnippetToolbar.tsx
@@ -94,6 +94,7 @@ export function SnippetToolbar({
               <DropdownMenuItem
                 key={template.id}
                 onClick={() => onCreateFromTemplate(template.id)}
+                data-testid={`snippet-template-react-${template.id}`}
               >
                 <div className="flex flex-col gap-1 py-1">
                   <span className="font-medium">{template.title}</span>