diff --git a/smartlog/src/commonMain/kotlin/com/jefryjacky/smartlog/SmartLog.kt b/smartlog/src/commonMain/kotlin/com/jefryjacky/smartlog/SmartLog.kt
index e2a5e1a..fea23b0 100644
--- a/smartlog/src/commonMain/kotlin/com/jefryjacky/smartlog/SmartLog.kt
+++ b/smartlog/src/commonMain/kotlin/com/jefryjacky/smartlog/SmartLog.kt
@@ -3,8 +3,10 @@ package com.jefryjacky.smartlog
 import com.jefryjacky.smartlog.di.AppContainer
 
 object SmartLog {
-    val printers: MutableList<Printer> by lazy {
-        mutableListOf(DatabasePrinter(AppContainer.logRepository))
+    val printers: MutableList<Printer> = mutableListOf()
+
+    fun init() {
+        printers.add(DatabasePrinter(AppContainer.logRepository))
     }
 
     fun v(tag: String, message: String){
diff --git a/smartlog/src/commonTest/kotlin/com/jefryjacky/smartlog/SmartLogTest.kt b/smartlog/src/commonTest/kotlin/com/jefryjacky/smartlog/SmartLogTest.kt
new file mode 100644
index 0000000..3e98c89
--- /dev/null
+++ b/smartlog/src/commonTest/kotlin/com/jefryjacky/smartlog/SmartLogTest.kt
@@ -0,0 +1,150 @@
+package com.jefryjacky.smartlog
+
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+
+class SmartLogTest {
+
+    private lateinit var mockPrinter: MockPrinter
+
+    @BeforeTest
+    fun setUp() {
+        mockPrinter = MockPrinter()
+        SmartLog.printers.clear()
+        SmartLog.printers.add(mockPrinter)
+    }
+
+    @Test
+    fun `test verbose logging`() {
+        // Given a printer is added to SmartLog (in setUp)
+
+        // When
+        SmartLog.v("TestTag", "This is a verbose message")
+
+        // Then
+        assertEquals(LogLevel.VERBOSE, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is a verbose message", mockPrinter.message)
+        assertNull(mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test debug logging`() {
+        // Given a printer is added to SmartLog (in setUp)
+
+        // When
+        SmartLog.d("TestTag", "This is a debug message")
+
+        // Then
+        assertEquals(LogLevel.DEBUG, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is a debug message", mockPrinter.message)
+        assertNull(mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test info logging`() {
+        // Given a printer is added to SmartLog (in setUp)
+
+        // When
+        SmartLog.i("TestTag", "This is an info message")
+
+        // Then
+        assertEquals(LogLevel.INFO, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is an info message", mockPrinter.message)
+        assertNull(mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test warn logging`() {
+        // Given a printer is added to SmartLog (in setUp)
+
+        // When
+        SmartLog.w("TestTag", "This is a warning message")
+
+        // Then
+        assertEquals(LogLevel.WARN, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is a warning message", mockPrinter.message)
+        assertNull(mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test error logging`() {
+        // Given a printer is added to SmartLog (in setUp)
+
+        // When
+        SmartLog.e("TestTag", "This is an error message")
+
+        // Then
+        assertEquals(LogLevel.ERROR, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is an error message", mockPrinter.message)
+        assertNull(mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test error logging with throwable`() {
+        // Given a printer is added to SmartLog (in setUp)
+        val throwable = RuntimeException("Test exception")
+
+        // When
+        SmartLog.e("TestTag", "This is an error message with throwable", throwable)
+
+        // Then
+        assertEquals(LogLevel.ERROR, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is an error message with throwable", mockPrinter.message)
+        assertEquals(throwable, mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test wtf logging`() {
+        // Given a printer is added to SmartLog (in setUp)
+
+        // When
+        SmartLog.wtf("TestTag", "This is an assert message")
+
+        // Then
+        assertEquals(LogLevel.ASSERT, mockPrinter.logLevel)
+        assertEquals("TestTag", mockPrinter.tag)
+        assertEquals("This is an assert message", mockPrinter.message)
+        assertNull(mockPrinter.throwable)
+    }
+
+    @Test
+    fun `test multiple printers`() {
+        // Given
+        val anotherMockPrinter = MockPrinter()
+        SmartLog.printers.add(anotherMockPrinter)
+
+        // When
+        SmartLog.i("MultiPrinter", "A message for multiple printers")
+
+        // Then
+        assertEquals(LogLevel.INFO, mockPrinter.logLevel)
+        assertEquals("MultiPrinter", mockPrinter.tag)
+        assertEquals("A message for multiple printers", mockPrinter.message)
+
+        assertEquals(LogLevel.INFO, anotherMockPrinter.logLevel)
+        assertEquals("MultiPrinter", anotherMockPrinter.tag)
+        assertEquals("A message for multiple printers", anotherMockPrinter.message)
+    }
+}
+
+class MockPrinter : Printer {
+    var logLevel: LogLevel? = null
+    var tag: String? = null
+    var message: String? = null
+    var throwable: Throwable? = null
+
+    override fun log(level: LogLevel, tag: String, message: String, throwable: Throwable?) {
+        this.logLevel = level
+        this.tag = tag
+        this.message = message
+        this.throwable = throwable
+    }
+}
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