Don't allow empty or null claimName or null value for claim expectations.

src/main/java/io/jsonwebtoken/impl/DefaultJwtParser.java

@@ -103,9 +103,9 @@ public class DefaultJwtParser implements JwtParser {
 
     @Override
     public JwtParser expect(String claimName, Object value) {
-        if (claimName != null && claimName.length() > 0 && value != null) {
+        Assert.hasText(claimName, "claim name cannot be null or empty.");
+        Assert.notNull(value, "The value cannot be null for claim name: " + claimName);
         expectedClaims.put(claimName, value);
-        }
 
         return this;
     }

src/test/groovy/io/jsonwebtoken/JwtParserTest.groovy

@@ -727,7 +727,7 @@ class JwtParserTest {
     }
 
     @Test
-    void testParseExpectIgnoreNullClaimName() {
+    void testParseExpectDontAllowNullClaimName() {
         def expectedClaimValue = 'A Most Awesome Claim Value'
 
         byte[] key = randomKey()
@@ -737,16 +737,22 @@ class JwtParserTest {
             setIssuer('Dummy').
             compact()
 
+        try {
             // expecting null claim name, but with value
             Jwt<Header, Claims> jwt = Jwts.parser().setSigningKey(key).
                 expect(null, expectedClaimValue).
                 parseClaimsJws(compact)
-
+            fail()
-        assertEquals jwt.getBody().getIssuer(), 'Dummy'
+        } catch (IllegalArgumentException e) {
+            assertEquals(
+                "claim name cannot be null or empty.",
+                e.getMessage()
+            )
+        }
     }
 
     @Test
-    void testParseExpectIgnoreEmptyClaimName() {
+    void testParseExpectDontAllowEmptyClaimName() {
         def expectedClaimValue = 'A Most Awesome Claim Value'
 
         byte[] key = randomKey()
@@ -756,16 +762,22 @@ class JwtParserTest {
             setIssuer('Dummy').
             compact()
 
+        try {
             // expecting null claim name, but with value
             Jwt<Header, Claims> jwt = Jwts.parser().setSigningKey(key).
                 expect("", expectedClaimValue).
                 parseClaimsJws(compact)
-
+            fail()
-        assertEquals jwt.getBody().getIssuer(), 'Dummy'
+        } catch (IllegalArgumentException e) {
+            assertEquals(
+                "claim name cannot be null or empty.",
+                e.getMessage()
+            )
+        }
     }
 
     @Test
-    void testParseExpectIgnoreNullClaimValue() {
+    void testParseExpectDontAllowNullClaimValue() {
         def expectedClaimName = 'A Most Awesome Claim Name'
 
         byte[] key = randomKey()
@@ -775,12 +787,18 @@ class JwtParserTest {
             setIssuer('Dummy').
             compact()
 
+        try {
             // expecting claim name, but with null value
             Jwt<Header, Claims> jwt = Jwts.parser().setSigningKey(key).
                 expect(expectedClaimName, null).
                 parseClaimsJws(compact)
-
+            fail()
-        assertEquals jwt.getBody().getIssuer(), 'Dummy'
+        } catch (IllegalArgumentException e) {
+            assertEquals(
+                "The value cannot be null for claim name: " + expectedClaimName,
+                e.getMessage()
+            )
+        }
     }
 
     @Test