com.github.mike10004.xvfbtesting.XvfbRule Maven / Gradle / Ivy
/*
* (c) 2016 mike chaberski
*/
package com.github.mike10004.xvfbtesting;
import com.github.mike10004.nativehelper.Platforms;
import com.github.mike10004.xvfbmanager.XvfbController;
import com.github.mike10004.xvfbmanager.XvfbException;
import com.github.mike10004.xvfbmanager.XvfbManager;
import org.junit.rules.ExternalResource;
import org.junit.rules.TemporaryFolder;
import javax.annotation.Nullable;
import java.io.IOException;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
public class XvfbRule extends ExternalResource {
private final TemporaryFolder temporaryFolder;
private final @Nullable Integer initialDisplayNumber;
private final XvfbManager xvfbManager;
private transient volatile XvfbController xvfbController;
private final boolean disabled;
private final StartMode startMode;
/**
* Creates a default rule instance that auto-selects the display number.
* Use a {@link #builder() builder} if you want to customize the
* {@link XvfbManager manager} instance, specify the display number, or
* customize other aspects of operation.
*/
public XvfbRule() {
this(builder());
}
private XvfbRule(Builder builder) {
this.xvfbManager = checkNotNull(builder.xvfbManager);
temporaryFolder = builder.temporaryFolder;
initialDisplayNumber = builder.displayNumber;
if (initialDisplayNumber != null) {
checkDisplayNumber(initialDisplayNumber);
}
this.disabled = builder.disabled;
checkArgument(disabled || !Platforms.getPlatform().isWindows(), "rule must be disabled on Windows platforms");
this.startMode = checkNotNull(builder.startMode, "startMode");
}
enum StartMode {
EAGER, LAZY
}
/**
* Returns a new builder of rule instances.
* @return a new builder instance
* @see Builder
*/
public static Builder builder() {
return new Builder();
}
/**
* Builder class for rule instances.
* @see XvfbRule
*/
public static class Builder {
private XvfbManager xvfbManager = new XvfbManager();
private boolean disabled;
private @Nullable Integer displayNumber;
private TemporaryFolder temporaryFolder = new TemporaryFolder();
private StartMode startMode = StartMode.EAGER;
/**
* Builds a rule instance.
* @return a new rule instance
*/
public XvfbRule build() {
return new XvfbRule(this);
}
/**
* Sets the manager instance to be used in building a rule.
* @param xvfbManager the manager to build the rule with
* @return this instance
*/
public Builder manager(XvfbManager xvfbManager) {
this.xvfbManager = checkNotNull(xvfbManager);
return this;
}
/**
* Sets the disabled flag to true.
* @return this instance
*/
public Builder disabled() {
return disabled(true);
}
/**
* Sets the disabled flag.
* @return this instance
*/
@SuppressWarnings("BooleanParameter")
public Builder disabled(boolean disabled) {
this.disabled = disabled;
return this;
}
/**
* Sets the disabledness
* @return this instance
*/
public Builder disabledOnWindows() {
if (Platforms.getPlatform().isWindows()) {
disabled = true;
}
return this;
}
/**
* Sets the display number to be automatically selected.
* This uses the {@code -displayfd} option to {@code Xvfb}.
* @return this instance
*/
public Builder autoDisplay() {
displayNumber = null;
return this;
}
/**
* Sets the display number of the rule instance being built.
* Use {@link #autoDisplay()} to automatically select an unused
* display number.
* @param displayNumber the display number
* @return this instance
*/
public Builder onDisplay(int displayNumber) {
this.displayNumber = checkDisplayNumber(displayNumber);
return this;
}
/**
* Delays starting the framebuffer daemon until the controller is requested.
* This sets a flag that causes the rule to delay {@link XvfbManager#start()}
* invocation until {@link #getController()} is invoked. Otherwise, {@code start()}
* will be invoked, and the controller created, in the "before" phase of the
* test lifecycle.
* @return this instance
*/
public Builder lazy() {
startMode = StartMode.LAZY;
return this;
}
}
protected static int checkDisplayNumber(Integer displayNum) {
checkNotNull(displayNum, "displayNum must be non-null");
checkArgument(displayNum >= 0, "displayNum >= 0 is required");
return displayNum;
}
@Override
protected void before() throws Throwable {
prepare();
}
protected void prepare() throws IOException {
checkState(xvfbController == null, "xvfbController already created");
if (!disabled) {
if (startMode == StartMode.EAGER) {
reallyPrepare();
}
}
}
private void reallyPrepare() throws IOException {
temporaryFolder.create();
if (initialDisplayNumber != null) {
xvfbController = xvfbManager.start(initialDisplayNumber);
} else {
xvfbController = xvfbManager.start();
}
}
@Override
protected void after() {
cleanUp();
}
protected void cleanUp() {
XvfbController xvfbController_ = xvfbController;
xvfbController = null;
if (xvfbController_ != null) {
xvfbController_.stop();
}
temporaryFolder.delete();
}
/**
* Gets the controller instance.
* @return the controller; never null
* @throws IllegalStateException if controller has not been created yet
* @throws XvfbException if start mode is lazy but {@link XvfbManager#start()} threw an exception
*/
public XvfbController getController() throws XvfbException {
if (disabled) {
return DisabledXvfbController.getInstance();
} else {
XvfbController xvfbController_ = xvfbController;
if (xvfbController_ == null) {
checkState(startMode == StartMode.LAZY, "must invoke before()/prepare() before getController() unless start mode is lazy");
try {
reallyPrepare();
xvfbController_ = xvfbController;
assert xvfbController_ != null : "controller should be initialized here";
} catch (IOException e) {
throw new LazyPreparationException(e);
}
}
return xvfbController_;
}
}
private static class LazyPreparationException extends XvfbException {
public LazyPreparationException(Throwable cause) {
super("lazy preparation failed", cause);
}
}
}