Add test for validation regex

scm-webapp/src/test/java/sonia/scm/api/v2/ValidationConstraints_IllegalCharactersTest.java

@@ -0,0 +1,47 @@
+package sonia.scm.api.v2;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import static java.util.Arrays.asList;
+import static org.junit.Assert.assertFalse;
+import static sonia.scm.api.v2.ValidationConstraints.USER_GROUP_PATTERN;
+
+@RunWith(Parameterized.class)
+public class ValidationConstraints_IllegalCharactersTest {
+
+  private static final List<Character> ACCEPTED_CHARS = asList('@', '_', '-', '.');
+
+  private final Pattern userGroupPattern=Pattern.compile(USER_GROUP_PATTERN);
+
+  private final String expression;
+
+  public ValidationConstraints_IllegalCharactersTest(String expression) {
+    this.expression = expression;
+  }
+
+  @Parameterized.Parameters(name = "{0}")
+  public static Collection<String[]> createParameters() {
+    return Stream.concat(IntStream.range(0x20, 0x2f).mapToObj(i -> (char) i),    // chars before '0'
+           Stream.concat(IntStream.range(0x3a, 0x40).mapToObj(i -> (char) i),    // chars between '9' and 'A'
+           Stream.concat(IntStream.range(0x5b, 0x60).mapToObj(i -> (char) i),    // chars between 'Z' and 'a'
+                         IntStream.range(0x7b, 0xff).mapToObj(i -> (char) i))))  // chars after 'z'
+      .filter(c -> !ACCEPTED_CHARS.contains(c))
+      .flatMap(c -> Stream.of("abc" + c + "xyz", "@" + c, c + "tail"))
+      .map(c -> new String[] {c})
+      .collect(Collectors.toList());
+  }
+
+  @Test
+  public void shouldNotAcceptCharactersBetween_Z_and_a() {
+    assertFalse(userGroupPattern.matcher(expression).matches());
+  }
+}