diff --git a/bazel/Android.bp b/bazel/Android.bp
index 05eddc1..d222d98 100644
--- a/bazel/Android.bp
+++ b/bazel/Android.bp
@@ -6,6 +6,9 @@
         "constants.go",
         "properties.go",
     ],
+    testSrcs: [
+        "aquery_test.go",
+    ],
     pluginFor: [
         "soong_build",
     ],
diff --git a/bazel/aquery.go b/bazel/aquery.go
index 404be8c..a196e8b 100644
--- a/bazel/aquery.go
+++ b/bazel/aquery.go
@@ -83,11 +83,15 @@
 // AqueryBuildStatements returns an array of BuildStatements which should be registered (and output
 // to a ninja file) to correspond one-to-one with the given action graph json proto (from a bazel
 // aquery invocation).
-func AqueryBuildStatements(aqueryJsonProto []byte) []BuildStatement {
+func AqueryBuildStatements(aqueryJsonProto []byte) ([]BuildStatement, error) {
 	buildStatements := []BuildStatement{}
 
 	var aqueryResult actionGraphContainer
-	json.Unmarshal(aqueryJsonProto, &aqueryResult)
+	err := json.Unmarshal(aqueryJsonProto, &aqueryResult)
+
+	if err != nil {
+		return nil, err
+	}
 
 	pathFragments := map[int]pathFragment{}
 	for _, pathFragment := range aqueryResult.PathFragments {
@@ -97,8 +101,7 @@
 	for _, artifact := range aqueryResult.Artifacts {
 		artifactPath, err := expandPathFragment(artifact.PathFragmentId, pathFragments)
 		if err != nil {
-			// TODO(cparsons): Better error handling.
-			panic(err.Error())
+			return nil, err
 		}
 		artifactIdToPath[artifact.Id] = artifactPath
 	}
@@ -110,15 +113,24 @@
 	for _, actionEntry := range aqueryResult.Actions {
 		outputPaths := []string{}
 		for _, outputId := range actionEntry.OutputIds {
-			// TODO(cparsons): Validate the id is present.
-			outputPaths = append(outputPaths, artifactIdToPath[outputId])
+			outputPath, exists := artifactIdToPath[outputId]
+			if !exists {
+				return nil, fmt.Errorf("undefined outputId %d", outputId)
+			}
+			outputPaths = append(outputPaths, outputPath)
 		}
 		inputPaths := []string{}
 		for _, inputDepSetId := range actionEntry.InputDepSetIds {
-			// TODO(cparsons): Validate the id is present.
-			for _, inputId := range depsetIdToArtifactIds[inputDepSetId] {
-				// TODO(cparsons): Validate the id is present.
-				inputPaths = append(inputPaths, artifactIdToPath[inputId])
+			inputArtifacts, exists := depsetIdToArtifactIds[inputDepSetId]
+			if !exists {
+				return nil, fmt.Errorf("undefined input depsetId %d", inputDepSetId)
+			}
+			for _, inputId := range inputArtifacts {
+				inputPath, exists := artifactIdToPath[inputId]
+				if !exists {
+					return nil, fmt.Errorf("undefined input artifactId %d", inputId)
+				}
+				inputPaths = append(inputPaths, inputPath)
 			}
 		}
 		buildStatement := BuildStatement{
@@ -130,7 +142,7 @@
 		buildStatements = append(buildStatements, buildStatement)
 	}
 
-	return buildStatements
+	return buildStatements, nil
 }
 
 func expandPathFragment(id int, pathFragmentsMap map[int]pathFragment) (string, error) {
@@ -140,7 +152,7 @@
 	for currId > 0 {
 		currFragment, ok := pathFragmentsMap[currId]
 		if !ok {
-			return "", fmt.Errorf("undefined path fragment id '%s'", currId)
+			return "", fmt.Errorf("undefined path fragment id %d", currId)
 		}
 		labels = append([]string{currFragment.Label}, labels...)
 		currId = currFragment.ParentId
diff --git a/bazel/aquery_test.go b/bazel/aquery_test.go
new file mode 100644
index 0000000..1bd6e67
--- /dev/null
+++ b/bazel/aquery_test.go
@@ -0,0 +1,450 @@
+// Copyright 2020 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 bazel
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestAqueryMultiArchGenrule(t *testing.T) {
+	// This input string is retrieved from a real build of bionic-related genrules.
+	const inputString = `
+{
+  "artifacts": [{
+    "id": 1,
+    "pathFragmentId": 1
+  }, {
+    "id": 2,
+    "pathFragmentId": 6
+  }, {
+    "id": 3,
+    "pathFragmentId": 8
+  }, {
+    "id": 4,
+    "pathFragmentId": 12
+  }, {
+    "id": 5,
+    "pathFragmentId": 19
+  }, {
+    "id": 6,
+    "pathFragmentId": 20
+  }, {
+    "id": 7,
+    "pathFragmentId": 21
+  }],
+  "actions": [{
+    "targetId": 1,
+    "actionKey": "ab53f6ecbdc2ee8cb8812613b63205464f1f5083f6dca87081a0a398c0f1ecf7",
+    "mnemonic": "Genrule",
+    "configurationId": 1,
+    "arguments": ["/bin/bash", "-c", "source ../bazel_tools/tools/genrule/genrule-setup.sh; ../sourceroot/bionic/libc/tools/gensyscalls.py arm ../sourceroot/bionic/libc/SYSCALLS.TXT \u003e bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-arm.S"],
+    "environmentVariables": [{
+      "key": "PATH",
+      "value": "/bin:/usr/bin:/usr/local/bin"
+    }],
+    "inputDepSetIds": [1],
+    "outputIds": [4],
+    "primaryOutputId": 4
+  }, {
+    "targetId": 2,
+    "actionKey": "9f4309ce165dac458498cb92811c18b0b7919782cc37b82a42d2141b8cc90826",
+    "mnemonic": "Genrule",
+    "configurationId": 1,
+    "arguments": ["/bin/bash", "-c", "source ../bazel_tools/tools/genrule/genrule-setup.sh; ../sourceroot/bionic/libc/tools/gensyscalls.py x86 ../sourceroot/bionic/libc/SYSCALLS.TXT \u003e bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-x86.S"],
+    "environmentVariables": [{
+      "key": "PATH",
+      "value": "/bin:/usr/bin:/usr/local/bin"
+    }],
+    "inputDepSetIds": [2],
+    "outputIds": [5],
+    "primaryOutputId": 5
+  }, {
+    "targetId": 3,
+    "actionKey": "50d6c586103ebeed3a218195540bcc30d329464eae36377eb82f8ce7c36ac342",
+    "mnemonic": "Genrule",
+    "configurationId": 1,
+    "arguments": ["/bin/bash", "-c", "source ../bazel_tools/tools/genrule/genrule-setup.sh; ../sourceroot/bionic/libc/tools/gensyscalls.py x86_64 ../sourceroot/bionic/libc/SYSCALLS.TXT \u003e bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-x86_64.S"],
+    "environmentVariables": [{
+      "key": "PATH",
+      "value": "/bin:/usr/bin:/usr/local/bin"
+    }],
+    "inputDepSetIds": [3],
+    "outputIds": [6],
+    "primaryOutputId": 6
+  }, {
+    "targetId": 4,
+    "actionKey": "f30cbe442f5216f4223cf16a39112cad4ec56f31f49290d85cff587e48647ffa",
+    "mnemonic": "Genrule",
+    "configurationId": 1,
+    "arguments": ["/bin/bash", "-c", "source ../bazel_tools/tools/genrule/genrule-setup.sh; ../sourceroot/bionic/libc/tools/gensyscalls.py arm64 ../sourceroot/bionic/libc/SYSCALLS.TXT \u003e bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-arm64.S"],
+    "environmentVariables": [{
+      "key": "PATH",
+      "value": "/bin:/usr/bin:/usr/local/bin"
+    }],
+    "inputDepSetIds": [4],
+    "outputIds": [7],
+    "primaryOutputId": 7
+  }],
+  "targets": [{
+    "id": 1,
+    "label": "@sourceroot//bionic/libc:syscalls-arm",
+    "ruleClassId": 1
+  }, {
+    "id": 2,
+    "label": "@sourceroot//bionic/libc:syscalls-x86",
+    "ruleClassId": 1
+  }, {
+    "id": 3,
+    "label": "@sourceroot//bionic/libc:syscalls-x86_64",
+    "ruleClassId": 1
+  }, {
+    "id": 4,
+    "label": "@sourceroot//bionic/libc:syscalls-arm64",
+    "ruleClassId": 1
+  }],
+  "depSetOfFiles": [{
+    "id": 1,
+    "directArtifactIds": [1, 2, 3]
+  }, {
+    "id": 2,
+    "directArtifactIds": [1, 2, 3]
+  }, {
+    "id": 3,
+    "directArtifactIds": [1, 2, 3]
+  }, {
+    "id": 4,
+    "directArtifactIds": [1, 2, 3]
+  }],
+  "configuration": [{
+    "id": 1,
+    "mnemonic": "k8-fastbuild",
+    "platformName": "k8",
+    "checksum": "485c362832c178e367d972177f68e69e0981e51e67ef1c160944473db53fe046"
+  }],
+  "ruleClasses": [{
+    "id": 1,
+    "name": "genrule"
+  }],
+  "pathFragments": [{
+    "id": 5,
+    "label": ".."
+  }, {
+    "id": 4,
+    "label": "sourceroot",
+    "parentId": 5
+  }, {
+    "id": 3,
+    "label": "bionic",
+    "parentId": 4
+  }, {
+    "id": 2,
+    "label": "libc",
+    "parentId": 3
+  }, {
+    "id": 1,
+    "label": "SYSCALLS.TXT",
+    "parentId": 2
+  }, {
+    "id": 7,
+    "label": "tools",
+    "parentId": 2
+  }, {
+    "id": 6,
+    "label": "gensyscalls.py",
+    "parentId": 7
+  }, {
+    "id": 11,
+    "label": "bazel_tools",
+    "parentId": 5
+  }, {
+    "id": 10,
+    "label": "tools",
+    "parentId": 11
+  }, {
+    "id": 9,
+    "label": "genrule",
+    "parentId": 10
+  }, {
+    "id": 8,
+    "label": "genrule-setup.sh",
+    "parentId": 9
+  }, {
+    "id": 18,
+    "label": "bazel-out"
+  }, {
+    "id": 17,
+    "label": "sourceroot",
+    "parentId": 18
+  }, {
+    "id": 16,
+    "label": "k8-fastbuild",
+    "parentId": 17
+  }, {
+    "id": 15,
+    "label": "bin",
+    "parentId": 16
+  }, {
+    "id": 14,
+    "label": "bionic",
+    "parentId": 15
+  }, {
+    "id": 13,
+    "label": "libc",
+    "parentId": 14
+  }, {
+    "id": 12,
+    "label": "syscalls-arm.S",
+    "parentId": 13
+  }, {
+    "id": 19,
+    "label": "syscalls-x86.S",
+    "parentId": 13
+  }, {
+    "id": 20,
+    "label": "syscalls-x86_64.S",
+    "parentId": 13
+  }, {
+    "id": 21,
+    "label": "syscalls-arm64.S",
+    "parentId": 13
+  }]
+}`
+	actualbuildStatements, _ := AqueryBuildStatements([]byte(inputString))
+	expectedBuildStatements := []BuildStatement{}
+	for _, arch := range []string{"arm", "arm64", "x86", "x86_64"} {
+		expectedBuildStatements = append(expectedBuildStatements,
+			BuildStatement{
+				Command: fmt.Sprintf(
+					"/bin/bash -c 'source ../bazel_tools/tools/genrule/genrule-setup.sh; ../sourceroot/bionic/libc/tools/gensyscalls.py %s ../sourceroot/bionic/libc/SYSCALLS.TXT > bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-%s.S'",
+					arch, arch),
+				OutputPaths: []string{
+					fmt.Sprintf("bazel-out/sourceroot/k8-fastbuild/bin/bionic/libc/syscalls-%s.S", arch),
+				},
+				InputPaths: []string{
+					"../sourceroot/bionic/libc/SYSCALLS.TXT",
+					"../sourceroot/bionic/libc/tools/gensyscalls.py",
+					"../bazel_tools/tools/genrule/genrule-setup.sh",
+				},
+				Env: []KeyValuePair{
+					KeyValuePair{Key: "PATH", Value: "/bin:/usr/bin:/usr/local/bin"},
+				},
+				Mnemonic: "Genrule",
+			})
+	}
+	assertBuildStatements(t, expectedBuildStatements, actualbuildStatements)
+}
+
+func TestInvalidOutputId(t *testing.T) {
+	const inputString = `
+{
+  "artifacts": [{
+    "id": 1,
+    "pathFragmentId": 1
+  }, {
+    "id": 2,
+    "pathFragmentId": 2
+  }],
+  "actions": [{
+    "targetId": 1,
+    "actionKey": "x",
+    "mnemonic": "x",
+    "arguments": ["touch", "foo"],
+    "inputDepSetIds": [1],
+    "outputIds": [3],
+    "primaryOutputId": 3
+  }],
+  "depSetOfFiles": [{
+    "id": 1,
+    "directArtifactIds": [1, 2]
+  }],
+  "pathFragments": [{
+    "id": 1,
+    "label": "one"
+  }, {
+    "id": 2,
+    "label": "two"
+  }]
+}`
+
+	_, err := AqueryBuildStatements([]byte(inputString))
+	assertError(t, err, "undefined outputId 3")
+}
+
+func TestInvalidInputDepsetId(t *testing.T) {
+	const inputString = `
+{
+  "artifacts": [{
+    "id": 1,
+    "pathFragmentId": 1
+  }, {
+    "id": 2,
+    "pathFragmentId": 2
+  }],
+  "actions": [{
+    "targetId": 1,
+    "actionKey": "x",
+    "mnemonic": "x",
+    "arguments": ["touch", "foo"],
+    "inputDepSetIds": [2],
+    "outputIds": [1],
+    "primaryOutputId": 1
+  }],
+  "depSetOfFiles": [{
+    "id": 1,
+    "directArtifactIds": [1, 2]
+  }],
+  "pathFragments": [{
+    "id": 1,
+    "label": "one"
+  }, {
+    "id": 2,
+    "label": "two"
+  }]
+}`
+
+	_, err := AqueryBuildStatements([]byte(inputString))
+	assertError(t, err, "undefined input depsetId 2")
+}
+
+func TestInvalidInputArtifactId(t *testing.T) {
+	const inputString = `
+{
+  "artifacts": [{
+    "id": 1,
+    "pathFragmentId": 1
+  }, {
+    "id": 2,
+    "pathFragmentId": 2
+  }],
+  "actions": [{
+    "targetId": 1,
+    "actionKey": "x",
+    "mnemonic": "x",
+    "arguments": ["touch", "foo"],
+    "inputDepSetIds": [1],
+    "outputIds": [1],
+    "primaryOutputId": 1
+  }],
+  "depSetOfFiles": [{
+    "id": 1,
+    "directArtifactIds": [1, 3]
+  }],
+  "pathFragments": [{
+    "id": 1,
+    "label": "one"
+  }, {
+    "id": 2,
+    "label": "two"
+  }]
+}`
+
+	_, err := AqueryBuildStatements([]byte(inputString))
+	assertError(t, err, "undefined input artifactId 3")
+}
+
+func TestInvalidPathFragmentId(t *testing.T) {
+	const inputString = `
+{
+  "artifacts": [{
+    "id": 1,
+    "pathFragmentId": 1
+  }, {
+    "id": 2,
+    "pathFragmentId": 2
+  }],
+  "actions": [{
+    "targetId": 1,
+    "actionKey": "x",
+    "mnemonic": "x",
+    "arguments": ["touch", "foo"],
+    "inputDepSetIds": [1],
+    "outputIds": [1],
+    "primaryOutputId": 1
+  }],
+  "depSetOfFiles": [{
+    "id": 1,
+    "directArtifactIds": [1, 2]
+  }],
+  "pathFragments": [{
+    "id": 1,
+    "label": "one"
+  }, {
+    "id": 2,
+    "label": "two",
+		"parentId": 3
+  }]
+}`
+
+	_, err := AqueryBuildStatements([]byte(inputString))
+	assertError(t, err, "undefined path fragment id 3")
+}
+
+func assertError(t *testing.T, err error, expected string) {
+	if err == nil || err.Error() != expected {
+		t.Errorf("expected error '%s', but got: %s", expected, err)
+	}
+}
+
+// Asserts that the given actual build statements match the given expected build statements.
+// Build statement equivalence is determined using buildStatementEquals.
+func assertBuildStatements(t *testing.T, expected []BuildStatement, actual []BuildStatement) {
+	if len(expected) != len(actual) {
+		t.Errorf("expected %d build statements, but got %d,\n expected: %s,\n actual: %s",
+			len(expected), len(actual), expected, actual)
+		return
+	}
+ACTUAL_LOOP:
+	for _, actualStatement := range actual {
+		for _, expectedStatement := range expected {
+			if buildStatementEquals(actualStatement, expectedStatement) {
+				continue ACTUAL_LOOP
+			}
+		}
+		t.Errorf("unexpected build statement %s.\n expected: %s",
+			actualStatement, expected)
+		return
+	}
+}
+
+func buildStatementEquals(first BuildStatement, second BuildStatement) bool {
+	if first.Mnemonic != second.Mnemonic {
+		return false
+	}
+	if first.Command != second.Command {
+		return false
+	}
+	// Ordering is significant for environment variables.
+	if !reflect.DeepEqual(first.Env, second.Env) {
+		return false
+	}
+	// Ordering is irrelevant for input and output paths, so compare sets.
+	if !reflect.DeepEqual(stringSet(first.InputPaths), stringSet(second.InputPaths)) {
+		return false
+	}
+	if !reflect.DeepEqual(stringSet(first.OutputPaths), stringSet(second.OutputPaths)) {
+		return false
+	}
+	return true
+}
+
+func stringSet(stringSlice []string) map[string]struct{} {
+	stringMap := make(map[string]struct{})
+	for _, s := range stringSlice {
+		stringMap[s] = struct{}{}
+	}
+	return stringMap
+}