fixes implicit multiplication test (#548)

Author: uklimaschewski

src/main/java/com/ezylang/evalex/functions/basic/CoalesceFunction.java

@@ -15,6 +15,9 @@
 */
 package com.ezylang.evalex.functions.basic;
 
+import static java.util.Arrays.stream;
+import static java.util.stream.Stream.of;
+
 import com.ezylang.evalex.Expression;
 import com.ezylang.evalex.data.EvaluationValue;
 import com.ezylang.evalex.functions.AbstractFunction;
@@ -27,22 +30,15 @@
  */
 @FunctionParameter(name = "value", isVarArg = true)
 public class CoalesceFunction extends AbstractFunction {
+
   @Override
   public EvaluationValue evaluate(
       Expression expression, Token functionToken, EvaluationValue... parameterValues) {
-    for (EvaluationValue parameter : parameterValues) {
-      if (parameter.isArrayValue()) {
-        for (EvaluationValue element : parameter.getArrayValue()) {
-          if (!element.isNullValue()) {
-            return element;
-          }
-        }
-      } else {
-        if (!parameter.isNullValue()) {
-          return parameter;
-        }
-      }
-    }
-    return EvaluationValue.NULL_VALUE;
+
+    return stream(parameterValues)
+        .flatMap(v -> v.isArrayValue() ? v.getArrayValue().stream() : of(v))
+        .filter(v -> !v.isNullValue())
+        .findFirst()
+        .orElse(EvaluationValue.NULL_VALUE);
   }
 }

src/test/java/com/ezylang/evalex/config/TestConfigurationProvider.java

@@ -39,7 +39,8 @@ public class TestConfigurationProvider {
               Map.entry("++", new PrefixPlusPlusOperator()),
               Map.entry("++", new PostfixPlusPlusOperator()),
               Map.entry("?", new PostfixQuestionOperator()))
-          .withAdditionalFunctions(Map.entry("TEST", new DummyFunction()));
+          .withAdditionalFunctions(
+              Map.entry("TEST", new DummyFunction()), Map.entry("F", new DummyFunction()));
 
   public static final ExpressionConfiguration GermanConfiguration =
       ExpressionConfiguration.builder()

src/test/java/com/ezylang/evalex/functions/basic/BasicFunctionsTest.java

@@ -390,17 +390,18 @@ void testCoalesce(String expression, String expectedResult)
   }
 
   @Test
-  void testCoalesceWithArray()
-      throws EvaluationException, ParseException {
-    EvaluationValue evaluationValue = new Expression("COALESCE(A, B, C)",
-        TestConfigurationProvider.StandardConfigurationWithAdditionalTestOperators)
-        .with("A", null)
-        .with("B", Arrays.asList(null, "8", null, null))
-        .with("C", "7")
-        .evaluate();
+  void testCoalesceWithArray() throws EvaluationException, ParseException {
+    EvaluationValue evaluationValue =
+        new Expression(
+                "COALESCE(A, B, C)",
+                TestConfigurationProvider.StandardConfigurationWithAdditionalTestOperators)
+            .with("A", null)
+            .with("B", Arrays.asList(null, "8", null, null))
+            .with("C", "7")
+            .evaluate();
 
-      assertThat(evaluationValue.isNullValue()).isFalse();
-      assertThat(evaluationValue.getStringValue()).isEqualTo("8");
+    assertThat(evaluationValue.isNullValue()).isFalse();
+    assertThat(evaluationValue.getStringValue()).isEqualTo("8");
   }
 
   @ParameterizedTest