add test

src/main/java/org/cryptomator/common/PropertiesPreprocessor.java

@@ -1,5 +1,6 @@
 package org.cryptomator.common;
 
+import org.jetbrains.annotations.VisibleForTesting;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -27,7 +28,8 @@ public class PropertiesPreprocessor {
 		LOG.info("Preprocessed cryptomator properties.");
 	}
 
-	private static String process(String value) {
+	@VisibleForTesting
+	static String process(String value) {
 		return TEMPLATE.matcher(value).replaceAll(match -> //
 				switch (match.group(1)) {
 					case "appdir" -> ENV.get("APPDIR");

src/test/java/org/cryptomator/common/PropertiesPreprocessorTest.java

@@ -0,0 +1,24 @@
+package org.cryptomator.common;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.mockito.Mockito;
+
+public class PropertiesPreprocessorTest {
+
+	@ParameterizedTest
+	@CsvSource(value = """
+			org.example.@{mytest1}.test, org.example.@{mytest1}.test
+			@{only*word*digits*under_score\\},@{only*words*digits*under_score\\}
+			C:\\Users\\@{appdir}\\dir, C:\\Users\\\\dir
+			@{@{appdir}},@{}
+			Longer @{appdir} text with @{appdir}., Longer  text with .
+			""")
+	public void test(String propertyValue, String expected) {
+		var result = PropertiesPreprocessor.process(propertyValue);
+		Assertions.assertEquals(result, expected);
+	}
+
+}