Add has to document, add tests (#1070)

 JAVA-4799

Author: katcharov

driver-core/src/main/com/mongodb/client/model/expressions/DocumentExpression.java

@@ -33,6 +33,15 @@
 public interface DocumentExpression extends Expression {
 
     DocumentExpression setField(String fieldName, Expression exp);
+    /**
+     * True if {@code this} document has a field with the provided
+     * {@code fieldName}.
+     *
+     * @param fieldName the name of the field.
+     * @return the resulting value.
+     */
+    BooleanExpression has(String fieldName);
+
 
     DocumentExpression unsetField(String fieldName);
 

driver-core/src/main/com/mongodb/client/model/expressions/MqlExpression.java

@@ -597,7 +597,7 @@ public NumberExpression sum(final Function<? super T, ? extends NumberExpression
     @Override
     public NumberExpression multiply(final Function<? super T, ? extends NumberExpression> mapper) {
         MqlExpression<NumberExpression> array = (MqlExpression<NumberExpression>) this.map(mapper);
-        return array.reduce(of(0), (NumberExpression a, NumberExpression b) -> a.multiply(b));
+        return array.reduce(of(1), (NumberExpression a, NumberExpression b) -> a.multiply(b));
     }
 
     @Override
@@ -909,6 +909,12 @@ public BooleanExpression has(final StringExpression key) {
         return get(key).ne(ofRem());
     }
 
+
+    @Override
+    public BooleanExpression has(final String fieldName) {
+        return this.has(of(fieldName));
+    }
+
     static <R extends Expression> R ofRem() {
         // $$REMOVE is intentionally not exposed to users
         return new MqlExpression<>((cr) -> new MqlExpression.AstPlaceholder(new BsonString("$$REMOVE")))

driver-core/src/test/functional/com/mongodb/client/model/expressions/ArrayExpressionsFunctionalTest.java

@@ -200,6 +200,19 @@ public void reduceSumTest() {
                 ofIntegerArray().sum(a -> a));
     }
 
+    @Test
+    public void reduceMultiplyTest() {
+        assertExpression(
+                6,
+                ofIntegerArray(1, 2, 3).multiply(a -> a),
+                "{'$reduce': {'input': {'$map': {'input': [1, 2, 3], 'in': '$$this'}}, "
+                        + "'initialValue': 1, 'in': {'$multiply': ['$$value', '$$this']}}}");
+        // empty array:
+        assertExpression(
+                1,
+                ofIntegerArray().multiply(a -> a));
+    }
+
     @Test
     public void reduceMaxTest() {
         assertExpression(

driver-core/src/test/functional/com/mongodb/client/model/expressions/DocumentExpressionsFunctionalTest.java

@@ -261,4 +261,17 @@ public void asMapTest() {
         DocumentExpression d = ofDoc("{a: 1}");
         assertSame(d, d.asMap());
     }
+
+
+    @Test
+    public void hasTest() {
+        DocumentExpression d = ofDoc("{a: 1}");
+        assertExpression(
+                true,
+                d.has("a"),
+                "{'$ne': [{'$getField': {'input': {'$literal': {'a': 1}}, 'field': 'a'}}, '$$REMOVE']}");
+        assertExpression(
+                false,
+                d.has("not_a"));
+    }
 }

driver-core/src/test/functional/com/mongodb/client/model/expressions/MapExpressionsFunctionalTest.java

@@ -77,15 +77,15 @@ public void getSetMapTest() {
     }
 
     @Test
-    public void hasMapTest() {
+    public void hasTest() {
+        MapExpression<Expression> e = ofMap(BsonDocument.parse("{key: 1}"));
         assertExpression(
                 true,
-                mapKey123.has(of("key")),
-                "{'$ne': [{'$getField': {'input': {'$setField': {'field': 'key', 'input': "
-                        + "{'$literal': {}}, 'value': 123}}, 'field': 'key'}}, '$$REMOVE']}");
+                e.has(of("key")),
+                "{'$ne': [{'$getField': {'input': {'$literal': {'key': 1}}, 'field': 'key'}}, '$$REMOVE']}");
         assertExpression(
                 false,
-                mapKey123.has("not_key"));
+                e.has("not_key"));
     }
 
     @Test

driver-core/src/test/functional/com/mongodb/client/model/expressions/StringExpressionsFunctionalTest.java

@@ -130,6 +130,10 @@ public void substrTest() {
                 "abc".substring(1, 1 + 1),
                 of("abc").substr(of(1), of(1)),
                 "{'$substrCP': ['abc', 1, 1]}");
+        assertExpression(
+                "bc",
+                of("abc").substr(of(1), of(100)),
+                "{'$substrCP': ['abc', 1, 100]}");
 
         // unicode
         assertExpression(

driver-core/src/test/functional/com/mongodb/client/model/expressions/TypeExpressionsFunctionalTest.java

@@ -263,6 +263,24 @@ public void parseIntegerTest() {
         assertExpression(
                 longVal,
                 of(longVal + "").parseInteger());
+
+        // failures
+        assertThrows(MongoCommandException.class, () ->
+            assertExpression(
+                    "",
+                    of(BsonDocument.parse("{a:'1.5'}")).getString("a").parseInteger()));
+        assertThrows(MongoCommandException.class, () ->
+            assertExpression(
+                    "",
+                    of(BsonDocument.parse("{a:'not an integer'}")).getString("a").parseInteger()));
+        assertThrows(MongoCommandException.class, () ->
+            assertExpression(
+                    "",
+                    of("1.5").parseInteger()));
+        assertThrows(MongoCommandException.class, () ->
+            assertExpression(
+                    "",
+                    of("not an integer").parseInteger()));
     }
 
     // non-string