DATAREDIS-822 - Consider argument range in RedisCommand min/max arguments specification.

We now consider max argument specifications as upper bound and no longer as the exact number of required arguments.

Original pull request: #335.

Author: mp911de

src/main/java/org/springframework/data/redis/core/RedisCommand.java

@@ -29,6 +29,7 @@
  * @author Christoph Strobl
  * @author Thomas Darimont
  * @author Ninad Divadkar
+ * @author Mark Paluch
  * @since 1.3
  * @see Redis command list:
  *      https://github.com/antirez/redis/blob/93e7a130fc9594e41ccfc996b5eca7626ae5356a/src/redis.c#L119
@@ -280,10 +281,10 @@ public boolean requiresArguments() {
 	}
 
 	/**
-	 * @return {@literal true} if an exact number of arguments is expected
+	 * @return {@literal true} if an exact number of arguments is expected.
 	 */
 	public boolean requiresExactNumberOfArguments() {
-		return maxArgs >= 0;
+		return maxArgs == 0 || minArgs == maxArgs;
 	}
 
 	/**
@@ -346,6 +347,11 @@ public void validateArgumentCount(int nrArguments) {
 				throw new IllegalArgumentException(
 						String.format("%s command requires at least %s arguments.", this.name(), this.minArgs));
 			}
+
+			if (maxArgs != 0 && nrArguments > maxArgs) {
+				throw new IllegalArgumentException(
+						String.format("%s command requires at most %s arguments.", this.name(), this.maxArgs));
+			}
 		}
 	}
 

src/test/java/org/springframework/data/redis/core/RedisCommandUnitTests.java

@@ -23,8 +23,11 @@
 import org.junit.rules.ExpectedException;
 
 /**
+ * Unit tests for {@link RedisCommand}.
+ *
  * @author Christoph Strobl
  * @author Thomas Darimont
+ * @author Mark Paluch
  */
 public class RedisCommandUnitTests {
 
@@ -65,8 +68,25 @@ public void shouldNotThrowExceptionOnValidArgumentCount() {
 		RedisCommand.AUTH.validateArgumentCount(1);
 	}
 
+	@Test // DATAREDIS-822
+	public void shouldConsiderMinMaxArguments() {
+
+		RedisCommand.BITPOS.validateArgumentCount(2);
+		RedisCommand.BITPOS.validateArgumentCount(3);
+		RedisCommand.BITPOS.validateArgumentCount(4);
+	}
+
+	@Test // DATAREDIS-822
+	public void shouldReportArgumentMismatchIfMaxArgumentsExceeded() {
+
+		expectedException.expect(IllegalArgumentException.class);
+		expectedException.expectMessage("BITPOS command requires at most 4 arguments");
+
+		RedisCommand.BITPOS.validateArgumentCount(5);
+	}
+
 	@Test // DATAREDIS-73
-	public void shouldThrowExceptionOnInvalidArgumentCountWhenExpectedExcatMatch() {
+	public void shouldThrowExceptionOnInvalidArgumentCountWhenExpectedExactMatch() {
 
 		expectedException.expect(IllegalArgumentException.class);
 		expectedException.expectMessage("AUTH command requires 1 arguments");