stocks/client-database-android/src/androidTest/java/de/njsm/stocks/client/database/util/RandomnessProvider.java

98 lines
3.4 KiB
Java

/*
* stocks is client-server program to manage a household's food stock
* Copyright (C) 2019 The stocks developers
*
* This file is part of the stocks program suite.
*
* stocks is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* stocks is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
package de.njsm.stocks.client.database.util;
import junit.framework.AssertionFailedError;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;
import java.util.*;
import java.util.concurrent.ThreadLocalRandom;
public class RandomnessProvider implements TestRule {
private static final String SPECIAL_CHARACTER = "%";
private final Map<String, Integer> ids = new HashMap<>();
private final Map<String, Integer> nameCounter = new HashMap<>();
public int getId(String name, Integer... forbiddenValues) {
if (name.contains(SPECIAL_CHARACTER)) {
throw new IllegalArgumentException(name + " contains forbidden character '" + SPECIAL_CHARACTER + "'");
}
int result = getResult(forbiddenValues);
return ids.merge(computeName(name), result, (a, b) -> result);
}
private String computeName(String name) {
int counter = nameCounter.merge(name, 0, (presentValue, newValue) -> presentValue + 1);
return name + SPECIAL_CHARACTER + counter;
}
private int getResult(Integer... forbiddenValues) {
int result;
Set<Integer> setOfForbiddenValues = new HashSet<>(Arrays.asList(forbiddenValues));
setOfForbiddenValues.addAll(ids.values());
do {
result = ThreadLocalRandom.current().nextInt(1, 1000);
} while(setOfForbiddenValues.contains(result));
return result;
}
@Override
public Statement apply(Statement base, Description description) {
return new Statement() {
@Override
public void evaluate() throws Throwable {
try {
base.evaluate();
} catch (Throwable e) {
AssertionFailedError randomValues = new AssertionFailedError(renderRandomValues());
randomValues.setStackTrace(new StackTraceElement[0]);
e.addSuppressed(randomValues);
throw e;
}
}
};
}
private String renderRandomValues() {
StringBuilder builder = new StringBuilder();
builder.append("ids used:\n");
renderMap(builder, ids);
return builder.toString();
}
private void renderMap(StringBuilder builder, Map<String, Integer> map) {
for (Map.Entry<String, Integer> entry : map.entrySet()) {
builder.append(" ");
builder.append(entry.getKey());
builder.append(": ");
builder.append(entry.getValue());
builder.append("\n");
}
}
}