diff --git a/internal/domains/sensors/domain_test.go b/internal/domains/sensors/domain_test.go
index bf8ed13..12e08f1 100644
--- a/internal/domains/sensors/domain_test.go
+++ b/internal/domains/sensors/domain_test.go
@@ -195,6 +195,136 @@ func Test_SensorValidate(t *testing.T) {
 	}
 }
 
+func Test_SensorData_Validate(t *testing.T) {
+	type testCase struct {
+		name     string
+		given    SensorData
+		expected SensorData
+		expecErr bool
+	}
+
+	timestamp := time.Now()
+
+	tests := []testCase{
+		{
+			name: "success with all fields",
+			given: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(25.5),
+				Timestamp: ptr(timestamp),
+			},
+			expected: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(25.5),
+				Timestamp: ptr(timestamp),
+			},
+			expecErr: false,
+		},
+		{
+			name: "error when sensor_id is empty",
+			given: SensorData{
+				SensorID: "",
+				Value:    ptr(25.5),
+			},
+			expecErr: true,
+		},
+		{
+			name: "error when value is nil",
+			given: SensorData{
+				SensorID: "temp-001",
+				Value:    nil,
+			},
+			expecErr: true,
+		},
+		{
+			name: "default timestamp when nil",
+			given: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(30.0),
+				Timestamp: nil,
+			},
+			expected: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(30.0),
+				Timestamp: nil, // Will be set by Validate
+			},
+			expecErr: false,
+		},
+		{
+			name: "zero value is preserved",
+			given: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(0.0),
+				Timestamp: ptr(timestamp),
+			},
+			expected: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(0.0),
+				Timestamp: ptr(timestamp),
+			},
+			expecErr: false,
+		},
+		{
+			name: "negative value is valid",
+			given: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(-15.5),
+				Timestamp: ptr(timestamp),
+			},
+			expected: SensorData{
+				SensorID:  "temp-001",
+				Value:     ptr(-15.5),
+				Timestamp: ptr(timestamp),
+			},
+			expecErr: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.given.Validate()
+
+			if tt.expecErr && err == nil {
+				t.Errorf("expected error, got nil")
+				return
+			}
+
+			if !tt.expecErr && err != nil {
+				t.Errorf("unexpected error: %v", err)
+				return
+			}
+
+			if tt.expecErr {
+				return
+			}
+
+			if tt.given.SensorID != tt.expected.SensorID {
+				t.Errorf("SensorID: expected %q, got %q", tt.expected.SensorID, tt.given.SensorID)
+			}
+
+			if tt.given.Value == nil || tt.expected.Value == nil {
+				if tt.given.Value != tt.expected.Value {
+					t.Errorf("Value: expected %v, got %v", tt.expected.Value, tt.given.Value)
+				}
+			} else if *tt.given.Value != *tt.expected.Value {
+				t.Errorf("Value: expected %v, got %v", *tt.expected.Value, *tt.given.Value)
+			}
+
+			if tt.expected.Timestamp == nil && tt.given.Timestamp != nil {
+				if time.Since(*tt.given.Timestamp) > time.Minute {
+					t.Errorf("Timestamp: expected default to be approximately now, got %v", *tt.given.Timestamp)
+				}
+			} else if tt.given.Timestamp == nil || tt.expected.Timestamp == nil {
+				if tt.given.Timestamp != tt.expected.Timestamp {
+					t.Errorf("Timestamp: expected %v, got %v", tt.expected.Timestamp, tt.given.Timestamp)
+				}
+			} else if !tt.given.Timestamp.Equal(*tt.expected.Timestamp) {
+				t.Errorf("Timestamp: expected %v, got %v", *tt.expected.Timestamp, *tt.given.Timestamp)
+			}
+		})
+	}
+}
+
 func Test_SensorData_IsOutOfRangeAbove(t *testing.T) {
 	type testCase struct {
 		name     string