Console launcher should support NO_COLOR environment variable

[sormuras]

Support NO_COLOR environment variable as described by https://no-color.org in JUnit's console launcher.

[marcphilipp]

Team decision: Check if picocli supports this already and, if not, raise an issue.

[sormuras]

Seems to be the case: https://picocli.info/#_heuristics_for_enabling_ansi

[marcphilipp]

Team decision: Check if our Console Launcher already supports this or what would need to be done in order to do so.

[sormuras]

• $ java -jar junit-platform-console-standalone-1.10.3.jar engines

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junit-jupiter (org.junit.jupiter:junit-jupiter-engine:5.10.3)
junit-platform-suite (org.junit.platform:junit-platform-suite-engine:1.10.3)
junit-vintage (org.junit.vintage:junit-vintage-engine:5.10.3)

• $ export NO_COLOR=1
• $ java -jar junit-platform-console-standalone-1.10.3.jar engines

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junit-jupiter (org.junit.jupiter:junit-jupiter-engine:5.10.3)
junit-platform-suite (org.junit.platform:junit-platform-suite-engine:1.10.3)
junit-vintage (org.junit.vintage:junit-vintage-engine:5.10.3)

The console launcher already does support NO_COLOR.

[sbrannen]

The console launcher already does support NO_COLOR.

Cool! 👏

In light of that, I'm removing this from the 5.11 RC1 milestone.

[dhoard]

Based on my testing using 5.11, the NO_COLOR environment variable is not fully supported.

Shell

> export NO_COLOR=1
> export | grep NO_COLOR
declare -x NO_COLOR="1"
> java -cp "junit-platform-console-standalone-1.11.0.jar:tests/target/test-classes:tests/lib/*" org.junit.platform.console.ConsoleLauncher execute --scan-classpath -n "JUnit5"

Output

Code

Looking at the code, only the --disable-ansi-colors command line option is used to determine whether to use ANSI colors. If I use the command line option, ANSI colors are disabled.

junit5/junit-platform-console/src/main/java/org/junit/platform/console/options/AnsiColorOptionMixin.java

Lines 32 to 37 in 40bc1c4

	@Option(names = "--disable-ansi-colors", description = "Disable ANSI colors in output (not supported by all terminals).")
	public void setDisableAnsiColors(boolean disableAnsiColors) {
	if (disableAnsiColors) {
	commandSpec.commandLine().setColorScheme(defaultColorScheme(Ansi.OFF));
	}
	this.disableAnsiColors = disableAnsiColors;

[sormuras]

Thanks for reporting this, @dhoard - it's an initialization issue.

junit5/junit-platform-console/src/main/java/org/junit/platform/console/options/AnsiColorOptionMixin.java

Line 26 in abf5ac3

private boolean disableAnsiColors;

should read like: private boolean disableAnsiColors = System.getenv("NO_COLOR") != null; instead of being set to false. It would be even better to tap into PicoCLI's heuristic programmatically.

[sbrannen]

Closing as completed on main (5.12 M1) with backports to previous branches in:

• Backport "Console launcher should support NO_COLOR environment variable" #3989
• Backport "Console launcher should support NO_COLOR environment variable" #3992