test: add unit tests for chat history, edit helper, and code cleaning

- Introduce tests for chat history file handling, loading/saving, and error cases in cmd/chat_test.go
- Add tests for removeLastModifiedComments in cmd/edit_helper_test.go
- Add comprehensive tests for CleanCodeResponse in internal/grok/cleancode_test.go
- Update Makefile to centralize build artifacts in build/ directory for coverage reports and binary
- Adjust .gitignore to ignore chat_history.json and remove obsolete coverage file entries

.gitignore

@@ -5,6 +5,4 @@ grokkit
 *.log
 *.tmp
 .env
-coverage.out
-coverage.html
 chat_history.json

Makefile

@@ -4,14 +4,16 @@ test:
 	go test ./... -v
 
 test-cover:
-	go test ./... -coverprofile=coverage.out
-	go tool cover -html=coverage.out -o coverage.html
-	@echo "✅ Coverage report: open coverage.html in your browser"
+	@mkdir -p build
+	go test ./... -coverprofile=build/coverage.out
+	go tool cover -html=build/coverage.out -o build/coverage.html
+	@echo "✅ Coverage report: open build/coverage.html in your browser"
 
 test-agent:
 	go test -run TestAgent ./... -v
 
 build:
+	@mkdir -p build
 	go build -ldflags "-s -w" -trimpath -o build/grokkit .
 
 install: build
@@ -21,7 +23,7 @@ install: build
 	@echo "✅ grokkit installed to ~/.local/bin"
 
 clean:
-	rm -rf build/ coverage.out coverage.html
+	rm -rf build/
 
 help:
 	@echo "Available targets:"

cmd/chat_test.go

@@ -0,0 +1,93 @@
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestGetChatHistoryFile(t *testing.T) {
+	// Save original HOME
+	oldHome := os.Getenv("HOME")
+	defer os.Setenv("HOME", oldHome)
+
+	tmpDir := t.TempDir()
+	os.Setenv("HOME", tmpDir)
+
+	histFile := getChatHistoryFile()
+	expected := filepath.Join(tmpDir, ".config", "grokkit", "chat_history.json")
+
+	if histFile != expected {
+		t.Errorf("getChatHistoryFile() = %q, want %q", histFile, expected)
+	}
+}
+
+func TestLoadChatHistory_NoFile(t *testing.T) {
+	tmpDir := t.TempDir()
+	oldHome := os.Getenv("HOME")
+	os.Setenv("HOME", tmpDir)
+	defer os.Setenv("HOME", oldHome)
+
+	history := loadChatHistory()
+	if history != nil {
+		t.Errorf("loadChatHistory() expected nil for non-existent file, got %v", history)
+	}
+}
+
+func TestSaveAndLoadChatHistory(t *testing.T) {
+	tmpDir := t.TempDir()
+	oldHome := os.Getenv("HOME")
+	os.Setenv("HOME", tmpDir)
+	defer os.Setenv("HOME", oldHome)
+
+	// Create test messages
+	messages := []map[string]string{
+		{"role": "system", "content": "test system message"},
+		{"role": "user", "content": "hello"},
+		{"role": "assistant", "content": "hi there"},
+	}
+
+	// Save
+	err := saveChatHistory(messages)
+	if err != nil {
+		t.Fatalf("saveChatHistory() error: %v", err)
+	}
+
+	// Load
+	loaded := loadChatHistory()
+	if loaded == nil {
+		t.Fatal("loadChatHistory() returned nil")
+	}
+
+	if len(loaded) != len(messages) {
+		t.Errorf("loadChatHistory() length = %d, want %d", len(loaded), len(messages))
+	}
+
+	// Verify content
+	for i, msg := range loaded {
+		if msg["role"] != messages[i]["role"] {
+			t.Errorf("Message[%d] role = %q, want %q", i, msg["role"], messages[i]["role"])
+		}
+		if msg["content"] != messages[i]["content"] {
+			t.Errorf("Message[%d] content = %q, want %q", i, msg["content"], messages[i]["content"])
+		}
+	}
+}
+
+func TestLoadChatHistory_InvalidJSON(t *testing.T) {
+	tmpDir := t.TempDir()
+	oldHome := os.Getenv("HOME")
+	os.Setenv("HOME", tmpDir)
+	defer os.Setenv("HOME", oldHome)
+
+	// Create invalid JSON file
+	histDir := filepath.Join(tmpDir, ".config", "grokkit")
+	os.MkdirAll(histDir, 0755)
+	histFile := filepath.Join(histDir, "chat_history.json")
+	os.WriteFile(histFile, []byte("invalid json{{{"), 0644)
+
+	history := loadChatHistory()
+	if history != nil {
+		t.Errorf("loadChatHistory() expected nil for invalid JSON, got %v", history)
+	}
+}

cmd/edit_helper_test.go

@@ -0,0 +1,53 @@
+package cmd
+
+import (
+	"testing"
+)
+
+func TestRemoveLastModifiedComments(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "removes last modified comment",
+			input:    "// Last modified: 2024-01-01\npackage main\n\nfunc main() {}",
+			expected: "package main\n\nfunc main() {}",
+		},
+		{
+			name:     "removes multiple last modified comments",
+			input:    "// Last modified: 2024-01-01\npackage main\n// Last modified by: user\nfunc main() {}",
+			expected: "package main\nfunc main() {}",
+		},
+		{
+			name:     "preserves code without last modified",
+			input:    "package main\n\nfunc main() {}",
+			expected: "package main\n\nfunc main() {}",
+		},
+		{
+			name:     "handles empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "preserves other comments",
+			input:    "// This is a regular comment\npackage main\n// Last modified: 2024\n// Another comment\nfunc main() {}",
+			expected: "// This is a regular comment\npackage main\n// Another comment\nfunc main() {}",
+		},
+		{
+			name:     "handles line with only last modified",
+			input:    "Last modified: 2024-01-01",
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := removeLastModifiedComments(tt.input)
+			if result != tt.expected {
+				t.Errorf("removeLastModifiedComments() = %q, want %q", result, tt.expected)
+			}
+		})
+	}
+}

internal/grok/cleancode_test.go

@@ -0,0 +1,86 @@
+package grok
+
+import "testing"
+
+func TestCleanCodeResponse_Comprehensive(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "removes go markdown fences",
+			input:    "```go\npackage main\n\nfunc main() {}\n```",
+			expected: "package main\n\nfunc main() {}",
+		},
+		{
+			name:     "removes python markdown fences",
+			input:    "```python\ndef hello():\n    print('hello')\n```",
+			expected: "def hello():\n    print('hello')",
+		},
+		{
+			name:     "removes plain markdown fences",
+			input:    "```\nsome code\n```",
+			expected: "some code",
+		},
+		{
+			name:     "handles no fences",
+			input:    "func main() {}",
+			expected: "func main() {}",
+		},
+		{
+			name:     "preserves internal blank lines",
+			input:    "```\nline1\n\nline2\n\nline3\n```",
+			expected: "line1\n\nline2\n\nline3",
+		},
+		{
+			name:     "trims leading whitespace",
+			input:    "  \n\n```\ncode\n```",
+			expected: "code",
+		},
+		{
+			name:     "trims trailing whitespace",
+			input:    "```\ncode\n```\n\n  ",
+			expected: "code",
+		},
+		{
+			name:     "handles multiple languages",
+			input:    "```javascript\nconst x = 1;\n```",
+			expected: "const x = 1;",
+		},
+		{
+			name:     "handles fences with extra spaces",
+			input:    "```  \ncode\n```  ",
+			expected: "code",
+		},
+		{
+			name:     "removes only fence lines",
+			input:    "text before\n```go\ncode\n```\ntext after",
+			expected: "text before\n\ncode\n\ntext after",
+		},
+		{
+			name:     "handles empty input",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "handles only fences",
+			input:    "```\n```",
+			expected: "",
+		},
+		{
+			name:     "preserves code indentation",
+			input:    "```\nfunc main() {\n    fmt.Println(\"hello\")\n}\n```",
+			expected: "func main() {\n    fmt.Println(\"hello\")\n}",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := CleanCodeResponse(tt.input)
+			if result != tt.expected {
+				t.Errorf("CleanCodeResponse():\ngot:  %q\nwant: %q", result, tt.expected)
+			}
+		})
+	}
+}