test: add comprehensive test suite and fix failing tests

- Fix history tests with proper test isolation using temp files
- Fix CMD tests with proper string contains and simplified assertions
- Add missing test utilities and helper functions
- Improve test coverage across all packages
- Remove flaky tests and replace with robust alternatives"

internal/history/history_test.go

@@ -0,0 +1,96 @@
+package history
+
+import (
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+// createTestHistoryManager creates a history manager with a temporary file for testing
+func createTestHistoryManager(t *testing.T) *HistoryManager {
+	// Create temporary directory
+	tempDir := t.TempDir()
+	historyPath := filepath.Join(tempDir, "test_sshm_history.json")
+
+	hm := &HistoryManager{
+		historyPath: historyPath,
+		history:     &ConnectionHistory{Connections: make(map[string]ConnectionInfo)},
+	}
+
+	return hm
+}
+
+func TestNewHistoryManager(t *testing.T) {
+	hm, err := NewHistoryManager()
+	if err != nil {
+		t.Fatalf("NewHistoryManager() error = %v", err)
+	}
+	if hm == nil {
+		t.Fatal("NewHistoryManager() returned nil")
+	}
+	if hm.historyPath == "" {
+		t.Error("Expected historyPath to be set")
+	}
+}
+
+func TestHistoryManager_RecordConnection(t *testing.T) {
+	hm := createTestHistoryManager(t)
+
+	// Add a connection
+	err := hm.RecordConnection("testhost")
+	if err != nil {
+		t.Errorf("RecordConnection() error = %v", err)
+	}
+
+	// Check that the connection was added
+	lastUsed, exists := hm.GetLastConnectionTime("testhost")
+	if !exists || lastUsed.IsZero() {
+		t.Error("Expected connection to be recorded")
+	}
+}
+
+func TestHistoryManager_GetLastConnectionTime(t *testing.T) {
+	hm := createTestHistoryManager(t)
+
+	// Test with no connections
+	lastUsed, exists := hm.GetLastConnectionTime("nonexistent-testhost")
+	if exists || !lastUsed.IsZero() {
+		t.Error("Expected no connection for non-existent host")
+	}
+
+	// Add a connection
+	err := hm.RecordConnection("testhost")
+	if err != nil {
+		t.Errorf("RecordConnection() error = %v", err)
+	}
+
+	// Test with existing connection
+	lastUsed, exists = hm.GetLastConnectionTime("testhost")
+	if !exists || lastUsed.IsZero() {
+		t.Error("Expected non-zero time for existing host")
+	}
+
+	// Check that the time is recent (within last minute)
+	if time.Since(lastUsed) > time.Minute {
+		t.Error("Last used time seems too old")
+	}
+}
+
+func TestHistoryManager_GetConnectionCount(t *testing.T) {
+	hm := createTestHistoryManager(t)
+
+	// Add same host multiple times
+	for i := 0; i < 3; i++ {
+		err := hm.RecordConnection("testhost-count")
+		if err != nil {
+			t.Errorf("RecordConnection() error = %v", err)
+		}
+		time.Sleep(1 * time.Millisecond)
+	}
+
+	// Should have correct count
+	count := hm.GetConnectionCount("testhost-count")
+	if count != 3 {
+		t.Errorf("Expected connection count 3, got %d", count)
+	}
+}