Null vs undefined + jsonata.setOutputConvertNulls tests. #59

Author: uw4

src/test/java/com/dashjoin/jsonata/NullSafetyTest.java

@@ -1,6 +1,11 @@
 package com.dashjoin.jsonata;
 
 import static com.dashjoin.jsonata.Jsonata.jsonata;
+import static com.dashjoin.jsonata.Jsonata.NULL_VALUE;
+import static com.dashjoin.jsonata.JsonataTest.mapOf;
+import static com.dashjoin.jsonata.JsonataTest.evaluateJsonata;
+import static com.dashjoin.jsonata.JsonataTest.UNDEFINED;
+import com.dashjoin.jsonata.JsonataTest;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -72,4 +77,115 @@ public void testFilterNullLookup() {
           Arrays.asList(Map.of("content", "some"), Map.of()));
       Assertions.assertEquals(Map.of("content", "some"), x);
     }
+
+    @Test
+    public void testOutputConvertNulls() {
+        Jsonata j = jsonata("$");
+        Jsonata j2 = jsonata("$");
+        j2.setOutputConvertNulls(false);
+
+        Assertions.assertTrue(j.isOutputConvertNulls());
+        Assertions.assertFalse(j2.isOutputConvertNulls());
+
+        Object res, res2;
+        res = j.evaluate(Jsonata.NULL_VALUE);
+        res2 = j2.evaluate(Jsonata.NULL_VALUE);
+
+        Assertions.assertEquals(null, res);
+        Assertions.assertEquals(Jsonata.NULL_VALUE, res2);
+
+        res = j.evaluate(null);
+        res2 = j2.evaluate(null);
+
+        Assertions.assertEquals(null, res);
+        Assertions.assertEquals(null, res2);
+    }
+
+    /**
+     * Executes expression without output null conversion
+     */
+    Object executeJsonataRaw(String expression, Object input) {
+        var expr = jsonata(expression);
+        expr.setOutputConvertNulls(false);
+        var result = expr.evaluate(input);
+        return result;
+    }
+
+    @Test
+    public void testJavaNullVsUndefined() throws Exception {
+        JsonataTest test = new JsonataTest();
+
+        Assertions.assertTrue(test.runTestCase("test-undefined", mapOf(
+            "expr", "undefined",
+            "undefinedResult", true)));
+
+        Assertions.assertTrue(test.runTestCase("test-null", mapOf(
+            "expr", "null",
+            "result", null)));
+
+        // Test various evaluations raw vs cooked, returning null or undefined
+        var res = executeJsonataRaw("null", null);
+        Assertions.assertEquals(Jsonata.NULL_VALUE, res);
+        
+        res = executeJsonataRaw("$", NULL_VALUE);
+        Assertions.assertEquals(Jsonata.NULL_VALUE, res);
+        
+        res = executeJsonataRaw("$", null);
+        Assertions.assertEquals(null, res);
+
+        res = executeJsonataRaw("no_match", null);
+        Assertions.assertEquals(null, res);
+
+        res = evaluateJsonata("null", null, null);
+        Assertions.assertNull(res);
+
+        res = evaluateJsonata("no_match", null, null);
+        Assertions.assertEquals(UNDEFINED, res);
+
+        res = evaluateJsonata("{}.a", null, null);
+        Assertions.assertEquals(UNDEFINED, res);
+
+        res = executeJsonataRaw("{\"a\":null}.a", null);
+        Assertions.assertEquals(Jsonata.NULL_VALUE, res);
+
+        res = evaluateJsonata("{\"a\":null}.a", null, null);
+        Assertions.assertEquals(null, res);
+
+        res = executeJsonataRaw("{\"a\":null}.b", null);
+        Assertions.assertNull(res);
+
+        res = evaluateJsonata("{\"a\":null}.b", null, null);
+        Assertions.assertEquals(UNDEFINED, res);
+
+        res = evaluateJsonata("[a,null,b][0]", null, null);
+        Assertions.assertEquals(null, res);
+
+        res = executeJsonataRaw("$[1]", List.of(42, Jsonata.NULL_VALUE));
+        Assertions.assertEquals(NULL_VALUE, res);
+
+        res = executeJsonataRaw("$[2]", List.of(42, Jsonata.NULL_VALUE));
+        Assertions.assertEquals(null, res);
+
+        res = evaluateJsonata("$[2]", List.of(42, Jsonata.NULL_VALUE), null);
+        Assertions.assertEquals(UNDEFINED, res);
+
+        res = jsonata("$").evaluate(Jsonata.NULL_VALUE);
+        Assertions.assertNull(res);
+
+        //
+        res = executeJsonataRaw("{'a':$}", Jsonata.NULL_VALUE);
+        Assertions.assertEquals(Jsonata.NULL_VALUE, ((Map)res).get("a"));
+
+        res = executeJsonataRaw("{'a':$}", null);
+        Assertions.assertEquals("{}", ""+res);
+
+        res = executeJsonataRaw("{'a':{'b':$}}",null);
+        Assertions.assertEquals("{a={}}", ""+res);
+
+        res = executeJsonataRaw("[$]", List.of(Jsonata.NULL_VALUE, Jsonata.NULL_VALUE));
+        Assertions.assertEquals(List.of(Jsonata.NULL_VALUE, Jsonata.NULL_VALUE), res);
+
+        res = evaluateJsonata("[$]", List.of(Jsonata.NULL_VALUE, Jsonata.NULL_VALUE), null);
+        Assertions.assertEquals(Arrays.asList(null, null), res);
+    }
 }