diff --git a/android/config_bp2build_test.go b/android/config_bp2build_test.go
new file mode 100644
index 0000000..05a1798
--- /dev/null
+++ b/android/config_bp2build_test.go
@@ -0,0 +1,323 @@
+// Copyright 2021 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"android/soong/bazel"
+	"testing"
+)
+
+func TestExpandVars(t *testing.T) {
+	android_arm64_config := TestConfig("out", nil, "", nil)
+	android_arm64_config.BuildOS = Android
+	android_arm64_config.BuildArch = Arm64
+
+	testCases := []struct {
+		description     string
+		config          Config
+		stringScope     ExportedStringVariables
+		stringListScope ExportedStringListVariables
+		configVars      ExportedConfigDependingVariables
+		toExpand        string
+		expectedValues  []string
+	}{
+		{
+			description:    "no expansion for non-interpolated value",
+			toExpand:       "foo",
+			expectedValues: []string{"foo"},
+		},
+		{
+			description: "single level expansion for string var",
+			stringScope: ExportedStringVariables{
+				"foo": "bar",
+			},
+			toExpand:       "${foo}",
+			expectedValues: []string{"bar"},
+		},
+		{
+			description: "single level expansion with short-name for string var",
+			stringScope: ExportedStringVariables{
+				"foo": "bar",
+			},
+			toExpand:       "${config.foo}",
+			expectedValues: []string{"bar"},
+		},
+		{
+			description: "single level expansion string list var",
+			stringListScope: ExportedStringListVariables{
+				"foo": []string{"bar"},
+			},
+			toExpand:       "${foo}",
+			expectedValues: []string{"bar"},
+		},
+		{
+			description: "mixed level expansion for string list var",
+			stringScope: ExportedStringVariables{
+				"foo": "${bar}",
+				"qux": "hello",
+			},
+			stringListScope: ExportedStringListVariables{
+				"bar": []string{"baz", "${qux}"},
+			},
+			toExpand:       "${foo}",
+			expectedValues: []string{"baz hello"},
+		},
+		{
+			description: "double level expansion",
+			stringListScope: ExportedStringListVariables{
+				"foo": []string{"${bar}"},
+				"bar": []string{"baz"},
+			},
+			toExpand:       "${foo}",
+			expectedValues: []string{"baz"},
+		},
+		{
+			description: "double level expansion with a literal",
+			stringListScope: ExportedStringListVariables{
+				"a": []string{"${b}", "c"},
+				"b": []string{"d"},
+			},
+			toExpand:       "${a}",
+			expectedValues: []string{"d c"},
+		},
+		{
+			description: "double level expansion, with two variables in a string",
+			stringListScope: ExportedStringListVariables{
+				"a": []string{"${b} ${c}"},
+				"b": []string{"d"},
+				"c": []string{"e"},
+			},
+			toExpand:       "${a}",
+			expectedValues: []string{"d e"},
+		},
+		{
+			description: "triple level expansion with two variables in a string",
+			stringListScope: ExportedStringListVariables{
+				"a": []string{"${b} ${c}"},
+				"b": []string{"${c}", "${d}"},
+				"c": []string{"${d}"},
+				"d": []string{"foo"},
+			},
+			toExpand:       "${a}",
+			expectedValues: []string{"foo foo foo"},
+		},
+		{
+			description: "expansion with config depending vars",
+			configVars: ExportedConfigDependingVariables{
+				"a": func(c Config) string { return c.BuildOS.String() },
+				"b": func(c Config) string { return c.BuildArch.String() },
+			},
+			config:         android_arm64_config,
+			toExpand:       "${a}-${b}",
+			expectedValues: []string{"android-arm64"},
+		},
+		{
+			description: "double level multi type expansion",
+			stringListScope: ExportedStringListVariables{
+				"platform": []string{"${os}-${arch}"},
+				"const":    []string{"const"},
+			},
+			configVars: ExportedConfigDependingVariables{
+				"os":   func(c Config) string { return c.BuildOS.String() },
+				"arch": func(c Config) string { return c.BuildArch.String() },
+				"foo":  func(c Config) string { return "foo" },
+			},
+			config:         android_arm64_config,
+			toExpand:       "${const}/${platform}/${foo}",
+			expectedValues: []string{"const/android-arm64/foo"},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			output, _ := expandVar(testCase.config, testCase.toExpand, testCase.stringScope, testCase.stringListScope, testCase.configVars)
+			if len(output) != len(testCase.expectedValues) {
+				t.Errorf("Expected %d values, got %d", len(testCase.expectedValues), len(output))
+			}
+			for i, actual := range output {
+				expectedValue := testCase.expectedValues[i]
+				if actual != expectedValue {
+					t.Errorf("Actual value '%s' doesn't match expected value '%s'", actual, expectedValue)
+				}
+			}
+		})
+	}
+}
+
+func TestBazelToolchainVars(t *testing.T) {
+	testCases := []struct {
+		name        string
+		config      Config
+		vars        ExportedVariables
+		expectedOut string
+	}{
+		{
+			name: "exports strings",
+			vars: ExportedVariables{
+				exportedStringVars: ExportedStringVariables{
+					"a": "b",
+					"c": "d",
+				},
+			},
+			expectedOut: bazel.GeneratedBazelFileWarning + `
+
+_a = "b"
+
+_c = "d"
+
+constants = struct(
+    a = _a,
+    c = _c,
+)`,
+		},
+		{
+			name: "exports string lists",
+			vars: ExportedVariables{
+				exportedStringListVars: ExportedStringListVariables{
+					"a": []string{"b1", "b2"},
+					"c": []string{"d1", "d2"},
+				},
+			},
+			expectedOut: bazel.GeneratedBazelFileWarning + `
+
+_a = [
+    "b1",
+    "b2",
+]
+
+_c = [
+    "d1",
+    "d2",
+]
+
+constants = struct(
+    a = _a,
+    c = _c,
+)`,
+		},
+		{
+			name: "exports string lists dicts",
+			vars: ExportedVariables{
+				exportedStringListDictVars: ExportedStringListDictVariables{
+					"a": map[string][]string{"b1": {"b2"}},
+					"c": map[string][]string{"d1": {"d2"}},
+				},
+			},
+			expectedOut: bazel.GeneratedBazelFileWarning + `
+
+_a = {
+    "b1": ["b2"],
+}
+
+_c = {
+    "d1": ["d2"],
+}
+
+constants = struct(
+    a = _a,
+    c = _c,
+)`,
+		},
+		{
+			name: "exports dict with var refs",
+			vars: ExportedVariables{
+				exportedVariableReferenceDictVars: ExportedVariableReferenceDictVariables{
+					"a": map[string]string{"b1": "${b2}"},
+					"c": map[string]string{"d1": "${config.d2}"},
+				},
+			},
+			expectedOut: bazel.GeneratedBazelFileWarning + `
+
+_a = {
+    "b1": _b2,
+}
+
+_c = {
+    "d1": _d2,
+}
+
+constants = struct(
+    a = _a,
+    c = _c,
+)`,
+		},
+		{
+			name: "sorts across types with variable references last",
+			vars: ExportedVariables{
+				exportedStringVars: ExportedStringVariables{
+					"b": "b-val",
+					"d": "d-val",
+				},
+				exportedStringListVars: ExportedStringListVariables{
+					"c": []string{"c-val"},
+					"e": []string{"e-val"},
+				},
+				exportedStringListDictVars: ExportedStringListDictVariables{
+					"a": map[string][]string{"a1": {"a2"}},
+					"f": map[string][]string{"f1": {"f2"}},
+				},
+				exportedVariableReferenceDictVars: ExportedVariableReferenceDictVariables{
+					"aa": map[string]string{"b1": "${b}"},
+					"cc": map[string]string{"d1": "${config.d}"},
+				},
+			},
+			expectedOut: bazel.GeneratedBazelFileWarning + `
+
+_a = {
+    "a1": ["a2"],
+}
+
+_b = "b-val"
+
+_c = ["c-val"]
+
+_d = "d-val"
+
+_e = ["e-val"]
+
+_f = {
+    "f1": ["f2"],
+}
+
+_aa = {
+    "b1": _b,
+}
+
+_cc = {
+    "d1": _d,
+}
+
+constants = struct(
+    a = _a,
+    b = _b,
+    c = _c,
+    d = _d,
+    e = _e,
+    f = _f,
+    aa = _aa,
+    cc = _cc,
+)`,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			out := BazelToolchainVars(tc.config, tc.vars)
+			if out != tc.expectedOut {
+				t.Errorf("Expected \n%s, got \n%s", tc.expectedOut, out)
+			}
+		})
+	}
+}