diff --git a/sdk/bp_test.go b/sdk/bp_test.go
index c630c25..e1edc51 100644
--- a/sdk/bp_test.go
+++ b/sdk/bp_test.go
@@ -18,8 +18,142 @@
 	"testing"
 
 	"android/soong/android"
+
+	"github.com/google/blueprint/proptools"
 )
 
+func propertySetFixture() interface{} {
+	set := newPropertySet()
+	set.AddProperty("x", "taxi")
+	set.AddPropertyWithTag("y", 1729, "tag_y")
+	subset := set.AddPropertySet("sub")
+	subset.AddPropertyWithTag("x", "taxi", "tag_x")
+	subset.AddProperty("y", 1729)
+	return set
+}
+
+func intPtr(i int) *int { return &i }
+
+type propertyStruct struct {
+	X     *string
+	Y     *int
+	Unset *bool
+	Sub   struct {
+		X     *string
+		Y     *int
+		Unset *bool
+	}
+}
+
+func propertyStructFixture() interface{} {
+	str := &propertyStruct{}
+	str.X = proptools.StringPtr("taxi")
+	str.Y = intPtr(1729)
+	str.Sub.X = proptools.StringPtr("taxi")
+	str.Sub.Y = intPtr(1729)
+	return str
+}
+
+func checkPropertySetFixture(h *TestHelper, val interface{}, hasTags bool) {
+	set := val.(*bpPropertySet)
+	h.AssertDeepEquals("wrong x value", "taxi", set.getValue("x"))
+	h.AssertDeepEquals("wrong y value", 1729, set.getValue("y"))
+
+	subset := set.getValue("sub").(*bpPropertySet)
+	h.AssertDeepEquals("wrong sub.x value", "taxi", subset.getValue("x"))
+	h.AssertDeepEquals("wrong sub.y value", 1729, subset.getValue("y"))
+
+	if hasTags {
+		h.AssertDeepEquals("wrong y tag", "tag_y", set.getTag("y"))
+		h.AssertDeepEquals("wrong sub.x tag", "tag_x", subset.getTag("x"))
+	} else {
+		h.AssertDeepEquals("wrong y tag", nil, set.getTag("y"))
+		h.AssertDeepEquals("wrong sub.x tag", nil, subset.getTag("x"))
+	}
+}
+
+func TestAddPropertySimple(t *testing.T) {
+	h := &TestHelper{t}
+	set := newPropertySet()
+	for name, val := range map[string]interface{}{
+		"x":   "taxi",
+		"y":   1729,
+		"t":   true,
+		"f":   false,
+		"arr": []string{"a", "b", "c"},
+	} {
+		set.AddProperty(name, val)
+		h.AssertDeepEquals("wrong value", val, set.getValue(name))
+	}
+	h.AssertPanic("adding x again should panic",
+		func() { set.AddProperty("x", "taxi") })
+	h.AssertPanic("adding arr again should panic",
+		func() { set.AddProperty("arr", []string{"d"}) })
+}
+
+func TestAddPropertySubset(t *testing.T) {
+	h := &TestHelper{t}
+	getFixtureMap := map[string]func() interface{}{
+		"property set":    propertySetFixture,
+		"property struct": propertyStructFixture,
+	}
+
+	t.Run("add new subset", func(t *testing.T) {
+		for name, getFixture := range getFixtureMap {
+			t.Run(name, func(t *testing.T) {
+				set := propertySetFixture().(*bpPropertySet)
+				set.AddProperty("new", getFixture())
+				checkPropertySetFixture(h, set, true)
+				checkPropertySetFixture(h, set.getValue("new"), name == "property set")
+			})
+		}
+	})
+
+	t.Run("merge existing subset", func(t *testing.T) {
+		for name, getFixture := range getFixtureMap {
+			t.Run(name, func(t *testing.T) {
+				set := newPropertySet()
+				subset := set.AddPropertySet("sub")
+				subset.AddProperty("flag", false)
+				subset.AddPropertySet("sub")
+				set.AddProperty("sub", getFixture())
+				merged := set.getValue("sub").(*bpPropertySet)
+				h.AssertDeepEquals("wrong flag value", false, merged.getValue("flag"))
+				checkPropertySetFixture(h, merged, name == "property set")
+			})
+		}
+	})
+
+	t.Run("add conflicting subset", func(t *testing.T) {
+		set := propertySetFixture().(*bpPropertySet)
+		h.AssertPanic("adding x again should panic",
+			func() { set.AddProperty("x", propertySetFixture()) })
+	})
+
+	t.Run("add non-pointer struct", func(t *testing.T) {
+		set := propertySetFixture().(*bpPropertySet)
+		str := propertyStructFixture().(*propertyStruct)
+		h.AssertPanic("adding a non-pointer struct should panic",
+			func() { set.AddProperty("new", *str) })
+	})
+}
+
+func TestAddPropertySetNew(t *testing.T) {
+	h := &TestHelper{t}
+	set := newPropertySet()
+	subset := set.AddPropertySet("sub")
+	subset.AddProperty("new", "d^^b")
+	h.AssertDeepEquals("wrong sub.new value", "d^^b", set.getValue("sub").(*bpPropertySet).getValue("new"))
+}
+
+func TestAddPropertySetExisting(t *testing.T) {
+	h := &TestHelper{t}
+	set := propertySetFixture().(*bpPropertySet)
+	subset := set.AddPropertySet("sub")
+	subset.AddProperty("new", "d^^b")
+	h.AssertDeepEquals("wrong sub.new value", "d^^b", set.getValue("sub").(*bpPropertySet).getValue("new"))
+}
+
 type removeFredTransformation struct {
 	identityTransformation
 }