diff --git a/pkg/error/database_test.go b/pkg/error/database_test.go
new file mode 100644
index 0000000..5fd2e1f
--- /dev/null
+++ b/pkg/error/database_test.go
@@ -0,0 +1,83 @@
+package error
+
+import "testing"
+
+func TestEntityAlreadyExists_Error(t *testing.T) {
+	tests := []struct {
+		name string
+		want string
+	}{
+		{
+			name: "Test : Valid error String",
+			want: "EntityAlreadyExists error",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := &EntityAlreadyExists{}
+			if got := e.Error(); got != tt.want {
+				t.Errorf("Error() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNoDataFound_Error(t *testing.T) {
+	tests := []struct {
+		name string
+		want string
+	}{
+		{
+			name: "Test : Valid error String",
+			want: "NoDataFound error",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := &NoDataFound{}
+			if got := e.Error(); got != tt.want {
+				t.Errorf("Error() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNoDataWritten_Error(t *testing.T) {
+	tests := []struct {
+		name string
+		want string
+	}{
+		{
+			name: "Test : Valid error String",
+			want: "NoDataWritten error",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := &NoDataWritten{}
+			if got := e.Error(); got != tt.want {
+				t.Errorf("Error() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNoRelationCreated_Error(t *testing.T) {
+	tests := []struct {
+		name string
+		want string
+	}{
+		{
+			name: "Test : Valid error String",
+			want: "relationship creation error",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := &NoRelationCreated{}
+			if got := e.Error(); got != tt.want {
+				t.Errorf("Error() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/pkg/error/validation_test.go b/pkg/error/validation_test.go
new file mode 100644
index 0000000..88e9d3c
--- /dev/null
+++ b/pkg/error/validation_test.go
@@ -0,0 +1,30 @@
+package error
+
+import "testing"
+
+func TestEntityValidationFailed_Error(t *testing.T) {
+	type fields struct {
+		Reason string
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   string
+	}{
+		{
+			name:   "Test 1: Reason",
+			fields: fields{Reason: "TEST ERROR"},
+			want:   "Entity validation failed: TEST ERROR",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			e := EntityValidationFailed{
+				Reason: tt.fields.Reason,
+			}
+			if got := e.Error(); got != tt.want {
+				t.Errorf("Error() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}