diff --git a/src/components/UnitTestDesigner.tsx b/src/components/UnitTestDesigner.tsx
index 6857755..a121c5f 100644
--- a/src/components/UnitTestDesigner.tsx
+++ b/src/components/UnitTestDesigner.tsx
@@ -2,16 +2,13 @@
 
 import { useState } from 'react'
 import { UnitTest, TestCase } from '@/types/project'
-import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
 import { Button } from '@/components/ui/button'
-import { Input } from '@/components/ui/input'
-import { Label } from '@/components/ui/label'
-import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'
-import { ScrollArea } from '@/components/ui/scroll-area'
-import { Textarea } from '@/components/ui/textarea'
-import { Plus, Trash, Flask, Sparkle } from '@phosphor-icons/react'
+import { Plus, Flask } from '@phosphor-icons/react'
 import { toast } from 'sonner'
-import { Badge } from '@/components/ui/badge'
+import unitTestDesignerCopy from '@/data/unit-test-designer.json'
+import { TestSuiteList } from '@/components/unit-test-designer/TestSuiteList'
+import { TestSuiteEditor } from '@/components/unit-test-designer/TestSuiteEditor'
+import { TestCasesPanel } from '@/components/unit-test-designer/TestCasesPanel'
 
 interface UnitTestDesignerProps {
   tests: UnitTest[]
@@ -25,7 +22,7 @@ export function UnitTestDesigner({ tests, onTestsChange }: UnitTestDesignerProps
   const handleAddTest = () => {
     const newTest: UnitTest = {
       id: `unit-test-${Date.now()}`,
-      name: 'New Test Suite',
+      name: unitTestDesignerCopy.defaults.testSuiteName,
       description: '',
       testType: 'component',
       targetFile: '',
@@ -53,8 +50,8 @@ export function UnitTestDesigner({ tests, onTestsChange }: UnitTestDesignerProps
     if (!selectedTest) return
     const newCase: TestCase = {
       id: `case-${Date.now()}`,
-      description: 'should work correctly',
-      assertions: ['expect(...).toBe(...)'],
+      description: unitTestDesignerCopy.defaults.testCaseDescription,
+      assertions: [unitTestDesignerCopy.defaults.assertion],
       setup: '',
       teardown: ''
     }
@@ -82,7 +79,7 @@ export function UnitTestDesigner({ tests, onTestsChange }: UnitTestDesignerProps
     const testCase = selectedTest.testCases.find(c => c.id === caseId)
     if (!testCase) return
     handleUpdateTestCase(caseId, {
-      assertions: [...testCase.assertions, 'expect(...).toBe(...)']
+      assertions: [...testCase.assertions, unitTestDesignerCopy.defaults.assertion]
     })
   }
 
@@ -105,289 +102,64 @@ export function UnitTestDesigner({ tests, onTestsChange }: UnitTestDesignerProps
   }
 
   const handleGenerateWithAI = async () => {
-    const description = prompt('Describe the component/function you want to test:')
+    const description = prompt(unitTestDesignerCopy.prompts.generateDescription)
     if (!description) return
 
     try {
-      toast.info('Generating test with AI...')
-      const promptText = `You are a unit test generator. Create tests based on: "${description}"
-
-Return a valid JSON object with a single property "test":
-{
-  "test": {
-    "id": "unique-id",
-    "name": "ComponentName/FunctionName Tests",
-    "description": "Test suite description",
-    "testType": "component" | "function" | "hook" | "integration",
-    "targetFile": "/path/to/file.tsx",
-    "testCases": [
-      {
-        "id": "case-id",
-        "description": "should render correctly",
-        "assertions": [
-          "expect(screen.getByText('Hello')).toBeInTheDocument()",
-          "expect(result).toBe(true)"
-        ],
-        "setup": "const { getByText } = render(<Component />)",
-        "teardown": "cleanup()"
-      }
-    ]
-  }
-}
-
-Create comprehensive test cases with appropriate assertions for React Testing Library or Vitest.`
-
+      toast.info(unitTestDesignerCopy.toasts.generating)
+      const promptText = unitTestDesignerCopy.prompts.generatePromptTemplate.replace(
+        '{{description}}',
+        description
+      )
       const response = await window.spark.llm(promptText, 'gpt-4o', true)
       const parsed = JSON.parse(response)
       onTestsChange([...tests, parsed.test])
       setSelectedTestId(parsed.test.id)
-      toast.success('Test suite generated successfully!')
+      toast.success(unitTestDesignerCopy.toasts.generateSuccess)
     } catch (error) {
       console.error(error)
-      toast.error('Failed to generate test')
+      toast.error(unitTestDesignerCopy.toasts.generateError)
     }
   }
 
-  const getTestTypeColor = (type: string) => {
-    const colors: Record<string, string> = {
-      component: 'bg-blue-500',
-      function: 'bg-green-500',
-      hook: 'bg-purple-500',
-      integration: 'bg-orange-500'
-    }
-    return colors[type] || 'bg-gray-500'
-  }
-
   return (
     <div className="h-full flex">
-      <div className="w-80 border-r border-border bg-card">
-        <div className="p-4 border-b border-border flex items-center justify-between">
-          <h2 className="font-semibold text-sm">Test Suites</h2>
-          <div className="flex gap-1">
-            <Button size="sm" variant="outline" onClick={handleGenerateWithAI}>
-              <Sparkle size={14} weight="duotone" />
-            </Button>
-            <Button size="sm" onClick={handleAddTest}>
-              <Plus size={14} />
-            </Button>
-          </div>
-        </div>
-        <ScrollArea className="h-[calc(100vh-200px)]">
-          <div className="p-2 space-y-1">
-            {tests.map(test => (
-              <div
-                key={test.id}
-                className={`p-3 rounded-md cursor-pointer flex items-start justify-between group ${
-                  selectedTestId === test.id ? 'bg-accent text-accent-foreground' : 'hover:bg-muted'
-                }`}
-                onClick={() => setSelectedTestId(test.id)}
-              >
-                <div className="flex-1 min-w-0">
-                  <div className="flex items-center gap-2 mb-1">
-                    <div className={`w-2 h-2 rounded-full ${getTestTypeColor(test.testType)}`} />
-                    <div className="font-medium text-sm truncate">{test.name}</div>
-                  </div>
-                  <div className="text-xs text-muted-foreground truncate">{test.targetFile || 'No file'}</div>
-                  <div className="text-xs text-muted-foreground">{test.testCases.length} cases</div>
-                </div>
-                <Button
-                  size="sm"
-                  variant="ghost"
-                  className="opacity-0 group-hover:opacity-100"
-                  onClick={(e) => {
-                    e.stopPropagation()
-                    handleDeleteTest(test.id)
-                  }}
-                >
-                  <Trash size={14} />
-                </Button>
-              </div>
-            ))}
-            {tests.length === 0 && (
-              <div className="p-8 text-center text-sm text-muted-foreground">
-                No test suites yet. Click + to create one.
-              </div>
-            )}
-          </div>
-        </ScrollArea>
-      </div>
+      <TestSuiteList
+        tests={tests}
+        selectedTestId={selectedTestId}
+        onSelectTest={setSelectedTestId}
+        onAddTest={handleAddTest}
+        onDeleteTest={handleDeleteTest}
+        onGenerateWithAI={handleGenerateWithAI}
+      />
 
       <div className="flex-1 p-6">
         {selectedTest ? (
           <div className="space-y-6">
-            <div className="flex items-center justify-between">
-              <h2 className="text-2xl font-bold">Test Suite Configuration</h2>
-              <Button variant="outline">
-                <Flask size={16} className="mr-2" weight="fill" />
-                Run Tests
-              </Button>
-            </div>
-
-            <Card>
-              <CardHeader>
-                <CardTitle>Test Suite Details</CardTitle>
-              </CardHeader>
-              <CardContent className="space-y-4">
-                <div className="space-y-2">
-                  <Label htmlFor="test-name">Test Suite Name</Label>
-                  <Input
-                    id="test-name"
-                    value={selectedTest.name}
-                    onChange={e => handleUpdateTest(selectedTest.id, { name: e.target.value })}
-                  />
-                </div>
-                <div className="space-y-2">
-                  <Label htmlFor="test-description">Description</Label>
-                  <Textarea
-                    id="test-description"
-                    value={selectedTest.description}
-                    onChange={e => handleUpdateTest(selectedTest.id, { description: e.target.value })}
-                    placeholder="What does this test suite cover?"
-                  />
-                </div>
-                <div className="grid grid-cols-2 gap-4">
-                  <div className="space-y-2">
-                    <Label htmlFor="test-type">Test Type</Label>
-                    <Select
-                      value={selectedTest.testType}
-                      onValueChange={(value: any) => handleUpdateTest(selectedTest.id, { testType: value })}
-                    >
-                      <SelectTrigger id="test-type">
-                        <SelectValue />
-                      </SelectTrigger>
-                      <SelectContent>
-                        <SelectItem value="component">Component</SelectItem>
-                        <SelectItem value="function">Function</SelectItem>
-                        <SelectItem value="hook">Hook</SelectItem>
-                        <SelectItem value="integration">Integration</SelectItem>
-                      </SelectContent>
-                    </Select>
-                  </div>
-                  <div className="space-y-2">
-                    <Label htmlFor="target-file">Target File</Label>
-                    <Input
-                      id="target-file"
-                      value={selectedTest.targetFile}
-                      onChange={e => handleUpdateTest(selectedTest.id, { targetFile: e.target.value })}
-                      placeholder="/src/components/Button.tsx"
-                    />
-                  </div>
-                </div>
-              </CardContent>
-            </Card>
-
-            <Card>
-              <CardHeader>
-                <div className="flex items-center justify-between">
-                  <div>
-                    <CardTitle>Test Cases</CardTitle>
-                    <CardDescription>Define individual test cases</CardDescription>
-                  </div>
-                  <Button size="sm" onClick={handleAddTestCase}>
-                    <Plus size={14} className="mr-1" />
-                    Add Test Case
-                  </Button>
-                </div>
-              </CardHeader>
-              <CardContent>
-                <ScrollArea className="h-[450px]">
-                  <div className="space-y-4">
-                    {selectedTest.testCases.map((testCase, index) => (
-                      <Card key={testCase.id}>
-                        <CardContent className="pt-4 space-y-3">
-                          <div className="flex items-center justify-between">
-                            <Badge variant="outline">Case {index + 1}</Badge>
-                            <Button
-                              size="sm"
-                              variant="ghost"
-                              onClick={() => handleDeleteTestCase(testCase.id)}
-                            >
-                              <Trash size={14} />
-                            </Button>
-                          </div>
-                          <div className="space-y-2">
-                            <Label>Description (it...)</Label>
-                            <Input
-                              value={testCase.description}
-                              onChange={e => handleUpdateTestCase(testCase.id, { description: e.target.value })}
-                              placeholder="should render correctly"
-                            />
-                          </div>
-                          <div className="space-y-2">
-                            <Label>Setup Code (optional)</Label>
-                            <Textarea
-                              value={testCase.setup || ''}
-                              onChange={e => handleUpdateTestCase(testCase.id, { setup: e.target.value })}
-                              placeholder="const { getByText } = render(<Component />)"
-                              className="font-mono text-xs"
-                              rows={2}
-                            />
-                          </div>
-                          <div className="space-y-2">
-                            <div className="flex items-center justify-between">
-                              <Label>Assertions</Label>
-                              <Button
-                                size="sm"
-                                variant="outline"
-                                onClick={() => handleAddAssertion(testCase.id)}
-                              >
-                                <Plus size={12} />
-                              </Button>
-                            </div>
-                            <div className="space-y-2">
-                              {testCase.assertions.map((assertion, assertionIndex) => (
-                                <div key={assertionIndex} className="flex gap-2">
-                                  <Input
-                                    value={assertion}
-                                    onChange={e => handleUpdateAssertion(testCase.id, assertionIndex, e.target.value)}
-                                    placeholder="expect(...).toBe(...)"
-                                    className="font-mono text-xs"
-                                  />
-                                  <Button
-                                    size="sm"
-                                    variant="ghost"
-                                    onClick={() => handleDeleteAssertion(testCase.id, assertionIndex)}
-                                  >
-                                    <Trash size={12} />
-                                  </Button>
-                                </div>
-                              ))}
-                            </div>
-                          </div>
-                          <div className="space-y-2">
-                            <Label>Teardown Code (optional)</Label>
-                            <Textarea
-                              value={testCase.teardown || ''}
-                              onChange={e => handleUpdateTestCase(testCase.id, { teardown: e.target.value })}
-                              placeholder="cleanup()"
-                              className="font-mono text-xs"
-                              rows={2}
-                            />
-                          </div>
-                        </CardContent>
-                      </Card>
-                    ))}
-                    {selectedTest.testCases.length === 0 && (
-                      <div className="py-12 text-center text-sm text-muted-foreground">
-                        No test cases yet. Click "Add Test Case" to create one.
-                      </div>
-                    )}
-                  </div>
-                </ScrollArea>
-              </CardContent>
-            </Card>
+            <TestSuiteEditor test={selectedTest} onUpdateTest={handleUpdateTest} />
+            <TestCasesPanel
+              testCases={selectedTest.testCases}
+              onAddTestCase={handleAddTestCase}
+              onDeleteTestCase={handleDeleteTestCase}
+              onUpdateTestCase={handleUpdateTestCase}
+              onAddAssertion={handleAddAssertion}
+              onUpdateAssertion={handleUpdateAssertion}
+              onDeleteAssertion={handleDeleteAssertion}
+            />
           </div>
         ) : (
           <div className="h-full flex items-center justify-center">
             <div className="text-center">
               <Flask size={48} className="mx-auto mb-4 text-muted-foreground" />
-              <p className="text-lg font-medium mb-2">No test suite selected</p>
+              <p className="text-lg font-medium mb-2">
+                {unitTestDesignerCopy.labels.noTestSuiteSelected}
+              </p>
               <p className="text-sm text-muted-foreground mb-4">
-                Create or select a test suite to configure
+                {unitTestDesignerCopy.labels.noTestSuiteSelectedBody}
               </p>
               <Button onClick={handleAddTest}>
                 <Plus size={16} className="mr-2" />
-                Create Test Suite
+                {unitTestDesignerCopy.labels.createTestSuite}
               </Button>
             </div>
           </div>
diff --git a/src/components/unit-test-designer/TestCasesPanel.tsx b/src/components/unit-test-designer/TestCasesPanel.tsx
new file mode 100644
index 0000000..ea37bef
--- /dev/null
+++ b/src/components/unit-test-designer/TestCasesPanel.tsx
@@ -0,0 +1,133 @@
+import { TestCase } from '@/types/project'
+import { Badge } from '@/components/ui/badge'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
+import { Input } from '@/components/ui/input'
+import { Label } from '@/components/ui/label'
+import { ScrollArea } from '@/components/ui/scroll-area'
+import { Textarea } from '@/components/ui/textarea'
+import { Plus, Trash } from '@phosphor-icons/react'
+import unitTestDesignerCopy from '@/data/unit-test-designer.json'
+
+interface TestCasesPanelProps {
+  testCases: TestCase[]
+  onAddTestCase: () => void
+  onDeleteTestCase: (caseId: string) => void
+  onUpdateTestCase: (caseId: string, updates: Partial<TestCase>) => void
+  onAddAssertion: (caseId: string) => void
+  onUpdateAssertion: (caseId: string, index: number, value: string) => void
+  onDeleteAssertion: (caseId: string, index: number) => void
+}
+
+export function TestCasesPanel({
+  testCases,
+  onAddTestCase,
+  onDeleteTestCase,
+  onUpdateTestCase,
+  onAddAssertion,
+  onUpdateAssertion,
+  onDeleteAssertion
+}: TestCasesPanelProps) {
+  return (
+    <Card>
+      <CardHeader>
+        <div className="flex items-center justify-between">
+          <div>
+            <CardTitle>{unitTestDesignerCopy.labels.testCases}</CardTitle>
+            <CardDescription>{unitTestDesignerCopy.labels.testCasesDescription}</CardDescription>
+          </div>
+          <Button size="sm" onClick={onAddTestCase}>
+            <Plus size={14} className="mr-1" />
+            {unitTestDesignerCopy.labels.addTestCase}
+          </Button>
+        </div>
+      </CardHeader>
+      <CardContent>
+        <ScrollArea className="h-[450px]">
+          <div className="space-y-4">
+            {testCases.map((testCase, index) => (
+              <Card key={testCase.id}>
+                <CardContent className="pt-4 space-y-3">
+                  <div className="flex items-center justify-between">
+                    <Badge variant="outline">
+                      {unitTestDesignerCopy.labels.case} {index + 1}
+                    </Badge>
+                    <Button
+                      size="sm"
+                      variant="ghost"
+                      onClick={() => onDeleteTestCase(testCase.id)}
+                    >
+                      <Trash size={14} />
+                    </Button>
+                  </div>
+                  <div className="space-y-2">
+                    <Label>{unitTestDesignerCopy.labels.caseDescription}</Label>
+                    <Input
+                      value={testCase.description}
+                      onChange={event => onUpdateTestCase(testCase.id, { description: event.target.value })}
+                      placeholder={unitTestDesignerCopy.placeholders.caseDescription}
+                    />
+                  </div>
+                  <div className="space-y-2">
+                    <Label>{unitTestDesignerCopy.labels.setupCode}</Label>
+                    <Textarea
+                      value={testCase.setup || ''}
+                      onChange={event => onUpdateTestCase(testCase.id, { setup: event.target.value })}
+                      placeholder={unitTestDesignerCopy.placeholders.setupCode}
+                      className="font-mono text-xs"
+                      rows={2}
+                    />
+                  </div>
+                  <div className="space-y-2">
+                    <div className="flex items-center justify-between">
+                      <Label>{unitTestDesignerCopy.labels.assertions}</Label>
+                      <Button size="sm" variant="outline" onClick={() => onAddAssertion(testCase.id)}>
+                        <Plus size={12} />
+                      </Button>
+                    </div>
+                    <div className="space-y-2">
+                      {testCase.assertions.map((assertion, assertionIndex) => (
+                        <div key={assertionIndex} className="flex gap-2">
+                          <Input
+                            value={assertion}
+                            onChange={event =>
+                              onUpdateAssertion(testCase.id, assertionIndex, event.target.value)
+                            }
+                            placeholder={unitTestDesignerCopy.placeholders.assertion}
+                            className="font-mono text-xs"
+                          />
+                          <Button
+                            size="sm"
+                            variant="ghost"
+                            onClick={() => onDeleteAssertion(testCase.id, assertionIndex)}
+                          >
+                            <Trash size={12} />
+                          </Button>
+                        </div>
+                      ))}
+                    </div>
+                  </div>
+                  <div className="space-y-2">
+                    <Label>{unitTestDesignerCopy.labels.teardownCode}</Label>
+                    <Textarea
+                      value={testCase.teardown || ''}
+                      onChange={event => onUpdateTestCase(testCase.id, { teardown: event.target.value })}
+                      placeholder={unitTestDesignerCopy.placeholders.teardownCode}
+                      className="font-mono text-xs"
+                      rows={2}
+                    />
+                  </div>
+                </CardContent>
+              </Card>
+            ))}
+            {testCases.length === 0 && (
+              <div className="py-12 text-center text-sm text-muted-foreground">
+                {unitTestDesignerCopy.labels.noTestCasesYet}
+              </div>
+            )}
+          </div>
+        </ScrollArea>
+      </CardContent>
+    </Card>
+  )
+}
diff --git a/src/components/unit-test-designer/TestSuiteEditor.tsx b/src/components/unit-test-designer/TestSuiteEditor.tsx
new file mode 100644
index 0000000..f543ea0
--- /dev/null
+++ b/src/components/unit-test-designer/TestSuiteEditor.tsx
@@ -0,0 +1,81 @@
+import { UnitTest } from '@/types/project'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import { Input } from '@/components/ui/input'
+import { Label } from '@/components/ui/label'
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'
+import { Textarea } from '@/components/ui/textarea'
+import { Flask } from '@phosphor-icons/react'
+import unitTestDesignerCopy from '@/data/unit-test-designer.json'
+
+interface TestSuiteEditorProps {
+  test: UnitTest
+  onUpdateTest: (testId: string, updates: Partial<UnitTest>) => void
+}
+
+export function TestSuiteEditor({ test, onUpdateTest }: TestSuiteEditorProps) {
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center justify-between">
+        <h2 className="text-2xl font-bold">{unitTestDesignerCopy.labels.testSuiteConfiguration}</h2>
+        <Button variant="outline">
+          <Flask size={16} className="mr-2" weight="fill" />
+          {unitTestDesignerCopy.labels.runTests}
+        </Button>
+      </div>
+
+      <Card>
+        <CardHeader>
+          <CardTitle>{unitTestDesignerCopy.labels.testSuiteDetails}</CardTitle>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <div className="space-y-2">
+            <Label htmlFor="test-name">{unitTestDesignerCopy.labels.testSuiteName}</Label>
+            <Input
+              id="test-name"
+              value={test.name}
+              onChange={event => onUpdateTest(test.id, { name: event.target.value })}
+            />
+          </div>
+          <div className="space-y-2">
+            <Label htmlFor="test-description">{unitTestDesignerCopy.labels.description}</Label>
+            <Textarea
+              id="test-description"
+              value={test.description}
+              onChange={event => onUpdateTest(test.id, { description: event.target.value })}
+              placeholder={unitTestDesignerCopy.placeholders.testSuiteDescription}
+            />
+          </div>
+          <div className="grid grid-cols-2 gap-4">
+            <div className="space-y-2">
+              <Label htmlFor="test-type">{unitTestDesignerCopy.labels.testType}</Label>
+              <Select
+                value={test.testType}
+                onValueChange={(value: UnitTest['testType']) => onUpdateTest(test.id, { testType: value })}
+              >
+                <SelectTrigger id="test-type">
+                  <SelectValue />
+                </SelectTrigger>
+                <SelectContent>
+                  <SelectItem value="component">{unitTestDesignerCopy.testTypes.component}</SelectItem>
+                  <SelectItem value="function">{unitTestDesignerCopy.testTypes.function}</SelectItem>
+                  <SelectItem value="hook">{unitTestDesignerCopy.testTypes.hook}</SelectItem>
+                  <SelectItem value="integration">{unitTestDesignerCopy.testTypes.integration}</SelectItem>
+                </SelectContent>
+              </Select>
+            </div>
+            <div className="space-y-2">
+              <Label htmlFor="target-file">{unitTestDesignerCopy.labels.targetFile}</Label>
+              <Input
+                id="target-file"
+                value={test.targetFile}
+                onChange={event => onUpdateTest(test.id, { targetFile: event.target.value })}
+                placeholder={unitTestDesignerCopy.placeholders.targetFile}
+              />
+            </div>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  )
+}
diff --git a/src/components/unit-test-designer/TestSuiteList.tsx b/src/components/unit-test-designer/TestSuiteList.tsx
new file mode 100644
index 0000000..1839900
--- /dev/null
+++ b/src/components/unit-test-designer/TestSuiteList.tsx
@@ -0,0 +1,91 @@
+import { UnitTest } from '@/types/project'
+import { Button } from '@/components/ui/button'
+import { ScrollArea } from '@/components/ui/scroll-area'
+import { Plus, Sparkle, Trash } from '@phosphor-icons/react'
+import unitTestDesignerCopy from '@/data/unit-test-designer.json'
+
+interface TestSuiteListProps {
+  tests: UnitTest[]
+  selectedTestId: string | null
+  onSelectTest: (testId: string) => void
+  onAddTest: () => void
+  onDeleteTest: (testId: string) => void
+  onGenerateWithAI: () => void
+}
+
+const getTestTypeColor = (type: string) => {
+  const colors: Record<string, string> = {
+    component: 'bg-blue-500',
+    function: 'bg-green-500',
+    hook: 'bg-purple-500',
+    integration: 'bg-orange-500'
+  }
+  return colors[type] || 'bg-gray-500'
+}
+
+export function TestSuiteList({
+  tests,
+  selectedTestId,
+  onSelectTest,
+  onAddTest,
+  onDeleteTest,
+  onGenerateWithAI
+}: TestSuiteListProps) {
+  return (
+    <div className="w-80 border-r border-border bg-card">
+      <div className="p-4 border-b border-border flex items-center justify-between">
+        <h2 className="font-semibold text-sm">{unitTestDesignerCopy.labels.testSuites}</h2>
+        <div className="flex gap-1">
+          <Button size="sm" variant="outline" onClick={onGenerateWithAI}>
+            <Sparkle size={14} weight="duotone" />
+          </Button>
+          <Button size="sm" onClick={onAddTest}>
+            <Plus size={14} />
+          </Button>
+        </div>
+      </div>
+      <ScrollArea className="h-[calc(100vh-200px)]">
+        <div className="p-2 space-y-1">
+          {tests.map(test => (
+            <div
+              key={test.id}
+              className={`p-3 rounded-md cursor-pointer flex items-start justify-between group ${
+                selectedTestId === test.id ? 'bg-accent text-accent-foreground' : 'hover:bg-muted'
+              }`}
+              onClick={() => onSelectTest(test.id)}
+            >
+              <div className="flex-1 min-w-0">
+                <div className="flex items-center gap-2 mb-1">
+                  <div className={`w-2 h-2 rounded-full ${getTestTypeColor(test.testType)}`} />
+                  <div className="font-medium text-sm truncate">{test.name}</div>
+                </div>
+                <div className="text-xs text-muted-foreground truncate">
+                  {test.targetFile || unitTestDesignerCopy.labels.noFile}
+                </div>
+                <div className="text-xs text-muted-foreground">
+                  {test.testCases.length} {unitTestDesignerCopy.labels.casesSuffix}
+                </div>
+              </div>
+              <Button
+                size="sm"
+                variant="ghost"
+                className="opacity-0 group-hover:opacity-100"
+                onClick={(event) => {
+                  event.stopPropagation()
+                  onDeleteTest(test.id)
+                }}
+              >
+                <Trash size={14} />
+              </Button>
+            </div>
+          ))}
+          {tests.length === 0 && (
+            <div className="p-8 text-center text-sm text-muted-foreground">
+              {unitTestDesignerCopy.labels.noTestSuitesYet}
+            </div>
+          )}
+        </div>
+      </ScrollArea>
+    </div>
+  )
+}
diff --git a/src/data/unit-test-designer.json b/src/data/unit-test-designer.json
new file mode 100644
index 0000000..7c00c7e
--- /dev/null
+++ b/src/data/unit-test-designer.json
@@ -0,0 +1,55 @@
+{
+  "labels": {
+    "testSuites": "Test Suites",
+    "testSuiteConfiguration": "Test Suite Configuration",
+    "testSuiteDetails": "Test Suite Details",
+    "testSuiteName": "Test Suite Name",
+    "description": "Description",
+    "testType": "Test Type",
+    "targetFile": "Target File",
+    "testCases": "Test Cases",
+    "testCasesDescription": "Define individual test cases",
+    "case": "Case",
+    "caseDescription": "Description (it...)",
+    "setupCode": "Setup Code (optional)",
+    "assertions": "Assertions",
+    "teardownCode": "Teardown Code (optional)",
+    "runTests": "Run Tests",
+    "addTestCase": "Add Test Case",
+    "createTestSuite": "Create Test Suite",
+    "noTestSuiteSelected": "No test suite selected",
+    "noTestSuiteSelectedBody": "Create or select a test suite to configure",
+    "noTestSuitesYet": "No test suites yet. Click + to create one.",
+    "noTestCasesYet": "No test cases yet. Click \"Add Test Case\" to create one.",
+    "noFile": "No file",
+    "casesSuffix": "cases"
+  },
+  "placeholders": {
+    "testSuiteDescription": "What does this test suite cover?",
+    "targetFile": "/src/components/Button.tsx",
+    "caseDescription": "should render correctly",
+    "setupCode": "const { getByText } = render(<Component />)",
+    "assertion": "expect(...).toBe(...)",
+    "teardownCode": "cleanup()"
+  },
+  "defaults": {
+    "testSuiteName": "New Test Suite",
+    "testCaseDescription": "should work correctly",
+    "assertion": "expect(...).toBe(...)"
+  },
+  "prompts": {
+    "generateDescription": "Describe the component/function you want to test:",
+    "generatePromptTemplate": "You are a unit test generator. Create tests based on: \"{{description}}\"\n\nReturn a valid JSON object with a single property \"test\":\n{\n  \"test\": {\n    \"id\": \"unique-id\",\n    \"name\": \"ComponentName/FunctionName Tests\",\n    \"description\": \"Test suite description\",\n    \"testType\": \"component\" | \"function\" | \"hook\" | \"integration\",\n    \"targetFile\": \"/path/to/file.tsx\",\n    \"testCases\": [\n      {\n        \"id\": \"case-id\",\n        \"description\": \"should render correctly\",\n        \"assertions\": [\n          \"expect(screen.getByText('Hello')).toBeInTheDocument()\",\n          \"expect(result).toBe(true)\"\n        ],\n        \"setup\": \"const { getByText } = render(<Component />)\",\n        \"teardown\": \"cleanup()\"\n      }\n    ]\n  }\n}\n\nCreate comprehensive test cases with appropriate assertions for React Testing Library or Vitest."
+  },
+  "toasts": {
+    "generating": "Generating test with AI...",
+    "generateSuccess": "Test suite generated successfully!",
+    "generateError": "Failed to generate test"
+  },
+  "testTypes": {
+    "component": "Component",
+    "function": "Function",
+    "hook": "Hook",
+    "integration": "Integration"
+  }
+}