| /* |
| * Copyright (C) 2013 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. |
| */ |
| package android.hardware.cts.helpers; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * Set of static helper methods for CTS tests. |
| */ |
| //TODO: Refactor this class into several more well defined helper classes, look at StatisticsUtils |
| public class SensorCtsHelper { |
| |
| private static final long NANOS_PER_MILLI = 1000000; |
| |
| /** |
| * Private constructor for static class. |
| */ |
| private SensorCtsHelper() {} |
| |
| /** |
| * Get the value of the 95th percentile using nearest rank algorithm. |
| * |
| * @throws IllegalArgumentException if the collection is null or empty |
| */ |
| public static <TValue extends Comparable<? super TValue>> TValue get95PercentileValue( |
| Collection<TValue> collection) { |
| validateCollection(collection); |
| |
| List<TValue> arrayCopy = new ArrayList<TValue>(collection); |
| Collections.sort(arrayCopy); |
| |
| // zero-based array index |
| int arrayIndex = (int) Math.round(arrayCopy.size() * 0.95 + .5) - 1; |
| |
| return arrayCopy.get(arrayIndex); |
| } |
| |
| /** |
| * Calculate the mean of a collection. |
| * |
| * @throws IllegalArgumentException if the collection is null or empty |
| */ |
| public static <TValue extends Number> double getMean(Collection<TValue> collection) { |
| validateCollection(collection); |
| |
| double sum = 0.0; |
| for(TValue value : collection) { |
| sum += value.doubleValue(); |
| } |
| return sum / collection.size(); |
| } |
| |
| /** |
| * Calculate the bias-corrected sample variance of a collection. |
| * |
| * @throws IllegalArgumentException if the collection is null or empty |
| */ |
| public static <TValue extends Number> double getVariance(Collection<TValue> collection) { |
| validateCollection(collection); |
| |
| double mean = getMean(collection); |
| ArrayList<Double> squaredDiffs = new ArrayList<Double>(); |
| for(TValue value : collection) { |
| double difference = mean - value.doubleValue(); |
| squaredDiffs.add(Math.pow(difference, 2)); |
| } |
| |
| double sum = 0.0; |
| for (Double value : squaredDiffs) { |
| sum += value; |
| } |
| return sum / (squaredDiffs.size() - 1); |
| } |
| |
| /** |
| * @return The (measured) sampling rate of a collection of {@link TestSensorEvent}. |
| */ |
| public static long getSamplingPeriodNs(List<TestSensorEvent> collection) { |
| int collectionSize = collection.size(); |
| if (collectionSize < 2) { |
| return 0; |
| } |
| TestSensorEvent firstEvent = collection.get(0); |
| TestSensorEvent lastEvent = collection.get(collectionSize - 1); |
| return (lastEvent.timestamp - firstEvent.timestamp) / (collectionSize - 1); |
| } |
| |
| /** |
| * Calculate the bias-corrected standard deviation of a collection. |
| * |
| * @throws IllegalArgumentException if the collection is null or empty |
| */ |
| public static <TValue extends Number> double getStandardDeviation( |
| Collection<TValue> collection) { |
| return Math.sqrt(getVariance(collection)); |
| } |
| |
| /** |
| * Convert a period to frequency in Hz. |
| */ |
| public static <TValue extends Number> double getFrequency(TValue period, TimeUnit unit) { |
| return 1000000000 / (TimeUnit.NANOSECONDS.convert(1, unit) * period.doubleValue()); |
| } |
| |
| /** |
| * Convert a frequency in Hz into a period. |
| */ |
| public static <TValue extends Number> double getPeriod(TValue frequency, TimeUnit unit) { |
| return 1000000000 / (TimeUnit.NANOSECONDS.convert(1, unit) * frequency.doubleValue()); |
| } |
| |
| /** |
| * @return The magnitude (norm) represented by the given array of values. |
| */ |
| public static double getMagnitude(float[] values) { |
| float sumOfSquares = 0.0f; |
| for (float value : values) { |
| sumOfSquares += value * value; |
| } |
| double magnitude = Math.sqrt(sumOfSquares); |
| return magnitude; |
| } |
| |
| /** |
| * Helper method to sleep for a given duration. |
| */ |
| public static void sleep(long duration, TimeUnit timeUnit) throws InterruptedException { |
| long durationNs = TimeUnit.NANOSECONDS.convert(duration, timeUnit); |
| Thread.sleep(durationNs / NANOS_PER_MILLI, (int) (durationNs % NANOS_PER_MILLI)); |
| } |
| |
| /** |
| * Format an assertion message. |
| * |
| * @param label the verification name |
| * @param environment the environment of the test |
| * |
| * @return The formatted string |
| */ |
| public static String formatAssertionMessage(String label, TestSensorEnvironment environment) { |
| return formatAssertionMessage(label, environment, "Failed"); |
| } |
| |
| /** |
| * Format an assertion message with a custom message. |
| * |
| * @param label the verification name |
| * @param environment the environment of the test |
| * @param format the additional format string |
| * @param params the additional format params |
| * |
| * @return The formatted string |
| */ |
| public static String formatAssertionMessage( |
| String label, |
| TestSensorEnvironment environment, |
| String format, |
| Object ... params) { |
| return formatAssertionMessage(label, environment, String.format(format, params)); |
| } |
| |
| /** |
| * Format an assertion message. |
| * |
| * @param label the verification name |
| * @param environment the environment of the test |
| * @param extras the additional information for the assertion |
| * |
| * @return The formatted string |
| */ |
| public static String formatAssertionMessage( |
| String label, |
| TestSensorEnvironment environment, |
| String extras) { |
| return String.format( |
| "%s | sensor='%s', samplingPeriod=%dus, maxReportLatency=%dus | %s", |
| label, |
| environment.getSensor().getName(), |
| environment.getRequestedSamplingPeriodUs(), |
| environment.getMaxReportLatencyUs(), |
| extras); |
| } |
| |
| /** |
| * @return A {@link File} representing a root directory to store sensor tests data. |
| */ |
| public static File getSensorTestDataDirectory() throws IOException { |
| File dataDirectory = new File(System.getenv("EXTERNAL_STORAGE"), "sensorTests/"); |
| return createDirectoryStructure(dataDirectory); |
| } |
| |
| /** |
| * Creates the directory structure for the given sensor test data sub-directory. |
| * |
| * @param subdirectory The sub-directory's name. |
| */ |
| public static File getSensorTestDataDirectory(String subdirectory) throws IOException { |
| File subdirectoryFile = new File(getSensorTestDataDirectory(), subdirectory); |
| return createDirectoryStructure(subdirectoryFile); |
| } |
| |
| /** |
| * Sanitizes a string so it can be used in file names. |
| * |
| * @param value The string to sanitize. |
| * @return The sanitized string. |
| * |
| * @throws SensorTestPlatformException If the string cannot be sanitized. |
| */ |
| public static String sanitizeStringForFileName(String value) |
| throws SensorTestPlatformException { |
| String sanitizedValue = value.replaceAll("[^a-zA-Z0-9_\\-]", "_"); |
| if (sanitizedValue.matches("_*")) { |
| throw new SensorTestPlatformException( |
| "Unable to sanitize string '%s' for file name.", |
| value); |
| } |
| return sanitizedValue; |
| } |
| |
| /** |
| * Ensures that the directory structure represented by the given {@link File} is created. |
| */ |
| private static File createDirectoryStructure(File directoryStructure) throws IOException { |
| directoryStructure.mkdirs(); |
| if (!directoryStructure.isDirectory()) { |
| throw new IOException("Unable to create directory structure for " |
| + directoryStructure.getAbsolutePath()); |
| } |
| return directoryStructure; |
| } |
| |
| /** |
| * Validate that a collection is not null or empty. |
| * |
| * @throws IllegalStateException if collection is null or empty. |
| */ |
| private static <T> void validateCollection(Collection<T> collection) { |
| if(collection == null || collection.size() == 0) { |
| throw new IllegalStateException("Collection cannot be null or empty"); |
| } |
| } |
| } |