health AIDL: add vts tests

This is a direct translation of the health 2.0
and 2.1 VTS tests.

Some slight modifications are made (e.g. use googlemock
matchers) to make the test code more readable.

Test: run on Pixel
Bug: 203245778

Change-Id: Ifc3799a04a6a09d0d53f400b60d19fbfe004a3e3
diff --git a/health/utils/libhealthtest/Android.bp b/health/utils/libhealthtest/Android.bp
new file mode 100644
index 0000000..dbe02d6
--- /dev/null
+++ b/health/utils/libhealthtest/Android.bp
@@ -0,0 +1,29 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// 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.
+
+// Utils library for VTS tests.
+cc_library_headers {
+    name: "libhealthtest_headers",
+    static_libs: [
+        "libgmock",
+        "libgtest",
+    ],
+    export_static_lib_headers: [
+        "libgmock",
+        "libgtest",
+    ],
+    export_include_dirs: [
+        "include",
+    ],
+}
diff --git a/health/utils/libhealthtest/include/health-test/TestUtils.h b/health/utils/libhealthtest/include/health-test/TestUtils.h
new file mode 100644
index 0000000..e69c411
--- /dev/null
+++ b/health/utils/libhealthtest/include/health-test/TestUtils.h
@@ -0,0 +1,149 @@
+#pragma once
+
+#include <chrono>
+
+#include <gtest/gtest.h>
+
+namespace android::hardware::health::test_utils {
+
+using testing::AssertionFailure;
+using testing::AssertionResult;
+using testing::AssertionSuccess;
+using std::chrono_literals::operator""s;
+
+// Needs to be called repeatedly within a period of time to ensure values are initialized.
+template <typename BatteryStatusType, typename BatteryStatusToStringFn>
+inline AssertionResult IsBatteryCurrentSignCorrect(const BatteryStatusType& status, int32_t current,
+                                                   bool acceptZeroCurrentAsUnknown,
+                                                   const BatteryStatusToStringFn& toString) {
+    // For IHealth.getCurrentNow/Average, if current is not available, it is expected that
+    // the error code is NOT_SUPPORTED, which is checked above. Hence, zero current is
+    // not treated as unknown values.
+    // For IHealth.getHealthInfo, if current is not available, health_info.current_* == 0.
+    // Caller of this function provides current.result == Result::SUCCESS. Hence, just skip the
+    // check.
+    if (current == 0 && acceptZeroCurrentAsUnknown) {
+        return AssertionSuccess()
+               << "current is 0, which indicates the value may not be available. Skipping.";
+    }
+
+    switch (status) {
+        case BatteryStatusType::UNKNOWN:
+            if (current != 0) {
+                // BatteryStatus may be UNKNOWN initially with a non-zero current value, but
+                // after it is initialized, it should be known.
+                return AssertionFailure()
+                       << "BatteryStatus is UNKNOWN but current is not 0. Actual: " << current;
+            }
+            break;
+        case BatteryStatusType::CHARGING:
+            if (current <= 0) {
+                return AssertionFailure()
+                       << "BatteryStatus is CHARGING but current is not positive. Actual: "
+                       << current;
+            }
+            break;
+        case BatteryStatusType::NOT_CHARGING:
+            if (current > 0) {
+                return AssertionFailure() << "BatteryStatus is " << toString(status)
+                                          << " but current is positive. Actual: " << current;
+            }
+            break;
+        case BatteryStatusType::DISCHARGING:
+            if (current >= 0) {
+                return AssertionFailure() << "BatteryStatus is " << toString(status)
+                                          << " but current is not negative. Actual: " << current;
+            }
+            break;
+        case BatteryStatusType::FULL:
+            // Battery current may be positive or negative depending on the load.
+            break;
+        default:
+            return AssertionFailure() << "Unknown BatteryStatus " << toString(status);
+    }
+
+    return AssertionSuccess() << "BatteryStatus is " << toString(status)
+                              << " and current has the correct sign: " << current;
+}
+
+inline AssertionResult IsValueSimilar(int32_t dividend, int32_t divisor, double factor) {
+    auto difference = abs(dividend - divisor);
+    if (difference > factor * abs(divisor)) {
+        return AssertionFailure() << dividend << " and " << divisor
+                                  << " are not similar (factor = " << factor << ")";
+    }
+    return AssertionSuccess() << dividend << " and " << divisor
+                              << " are similar (factor = " << factor << ")";
+}
+
+inline AssertionResult IsBatteryCurrentSimilar(int32_t currentNow, int32_t currentAverage,
+                                               double currentCompareFactor) {
+    // Check that the two values are similar. Note that the two tests uses a different
+    // divisor to ensure that they are actually pretty similar. For example,
+    // IsValueSimilar(5,10,0.4) returns true, but IsValueSimlar(10,5,0.4) returns false.
+    auto res = IsValueSimilar(currentNow, currentAverage, currentCompareFactor)
+               << " for now vs. average. Check units.";
+    if (!res) return res;
+    res = IsValueSimilar(currentAverage, currentNow, currentCompareFactor)
+          << " for average vs. now. Check units.";
+    if (!res) return res;
+    return AssertionSuccess() << "currentNow = " << currentNow
+                              << " and currentAverage = " << currentAverage
+                              << " are considered similar.";
+}
+
+// Test that f() returns AssertionSuccess() once in a given period of time.
+template <typename Duration, typename Function>
+inline AssertionResult SucceedOnce(Duration d, Function f) {
+    AssertionResult result = AssertionFailure() << "Function is never evaluated.";
+    auto end = std::chrono::system_clock::now() + d;
+    while (std::chrono::system_clock::now() <= end) {
+        result = f();
+        if (result) {
+            return result;
+        }
+        std::this_thread::sleep_for(2s);
+    }
+    return result;
+}
+
+template <typename BatteryStatusType, typename BatteryInfoType, typename BatteryStatusToStringFn>
+AssertionResult IsBatteryStatusCorrect(const BatteryStatusType& status,
+                                       const BatteryInfoType& batteryInfo,
+                                       const BatteryStatusToStringFn& toString) {
+    bool isConnected = batteryInfo.chargerAcOnline || batteryInfo.chargerUsbOnline ||
+                       batteryInfo.chargerWirelessOnline;
+
+    std::stringstream message;
+    message << "BatteryStatus is " << toString(status) << " and " << (isConnected ? "" : "no ")
+            << "power source is connected: ac=" << batteryInfo.chargerAcOnline
+            << ", usb=" << batteryInfo.chargerUsbOnline
+            << ", wireless=" << batteryInfo.chargerWirelessOnline;
+
+    switch (status) {
+        case BatteryStatusType::UNKNOWN: {
+            // Don't enforce anything on isConnected on unknown battery status.
+            // Battery-less devices must report UNKNOWN battery status, but may report true
+            // or false on isConnected.
+        } break;
+        case BatteryStatusType::CHARGING:
+        case BatteryStatusType::NOT_CHARGING:
+        case BatteryStatusType::FULL: {
+            if (!isConnected) {
+                return AssertionFailure() << message.str();
+            }
+        } break;
+        case BatteryStatusType::DISCHARGING: {
+            if (isConnected) {
+                return AssertionFailure() << message.str();
+            }
+        } break;
+        default: {
+            return AssertionFailure() << "Unknown battery status value " << toString(status);
+        } break;
+    }
+
+    return AssertionSuccess() << message.str();
+}
+
+}  // namespace android::hardware::health::test_utils