diff --git a/aht20/aht20_test.go b/aht20/aht20_test.go
index ef833bd..15efe42 100644
--- a/aht20/aht20_test.go
+++ b/aht20/aht20_test.go
@@ -7,13 +7,80 @@ import (
 	"testing"
 )
 
+const byteStatusInitialized = bitInitialized | 0x10
+
+func TestNewI2C(t *testing.T) {
+	type TestCase struct {
+		name string
+		ops  []i2ctest.IO
+	}
+
+	testCases := []TestCase{
+		{
+			name: "device already initialized",
+			ops: []i2ctest.IO{
+				// Read status
+				{Addr: deviceAddress, W: []byte{cmdStatus}, R: []byte{byteStatusInitialized}},
+			},
+		},
+		{
+			name: "device not initialized",
+			ops: []i2ctest.IO{
+				// Read status
+				{Addr: deviceAddress, W: []byte{cmdStatus}, R: []byte{0x00}},
+				// Initialize
+				{Addr: deviceAddress, W: argsInitialize},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			bus := i2ctest.Playback{Ops: tc.ops}
+			if dev, err := NewI2C(&bus, nil); err != nil {
+				t.Fatal(err)
+			} else if dev == nil {
+				t.Fatal("expected device")
+			}
+		})
+	}
+}
+
+func TestDev_IsInitialized(t *testing.T) {
+	bus := i2ctest.Playback{
+		Ops: []i2ctest.IO{
+			// Read status
+			{Addr: deviceAddress, W: []byte{cmdStatus}, R: []byte{byteStatusInitialized}},
+		},
+	}
+	dev := Dev{d: &i2c.Dev{Bus: &bus, Addr: deviceAddress}, opts: DefaultOpts}
+	if err, initialized := dev.IsInitialized(); err != nil {
+		t.Fatal(err)
+	} else if !initialized {
+		t.Fatal("expected initialized")
+	}
+}
+
+func TestDev_Initialize(t *testing.T) {
+	bus := i2ctest.Playback{
+		Ops: []i2ctest.IO{
+			// Initialize
+			{Addr: deviceAddress, W: argsInitialize},
+		},
+	}
+	dev := Dev{d: &i2c.Dev{Bus: &bus, Addr: deviceAddress}, opts: DefaultOpts}
+	if err := dev.Initialize(); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestDev_Sense(t *testing.T) {
 	bus := i2ctest.Playback{
 		Ops: []i2ctest.IO{
 			// Trigger measurement
 			{Addr: deviceAddress, W: argsMeasure},
 			// Read measurement
-			{Addr: deviceAddress, R: []byte{0x18, 0x75, 0x52, 0x05, 0x8E, 0x40, 0x7F}},
+			{Addr: deviceAddress, R: []byte{byteStatusInitialized, 0x75, 0x52, 0x05, 0x8E, 0x40, 0x7F}},
 		},
 	}
 	dev := Dev{d: &i2c.Dev{Bus: &bus, Addr: deviceAddress}, opts: DefaultOpts}
@@ -34,3 +101,16 @@ func TestDev_Sense(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestDev_SoftReset(t *testing.T) {
+	bus := i2ctest.Playback{
+		Ops: []i2ctest.IO{
+			// Soft reset
+			{Addr: deviceAddress, W: []byte{cmdSoftReset}},
+		},
+	}
+	dev := Dev{d: &i2c.Dev{Bus: &bus, Addr: deviceAddress}, opts: DefaultOpts}
+	if err := dev.SoftReset(); err != nil {
+		t.Fatal(err)
+	}
+}