add more tests for ElementSetter

kyaml/yaml/fns.go

@@ -41,10 +41,9 @@ func (a ElementAppender) Filter(rn *RNode) (*RNode, error) {
 	return nil, nil
 }
 
-// ElementSetter sets the value for an Element in an associative list. ElementSetter
-// will remove any elements which are empty.
+// ElementSetter sets the value for an Element in an associative list.
 // ElementSetter will append, replace or delete an element in an associative list.
-// To append, user a key-value pair that doesn't exist in the sequence. Note: this
+// To append, user a key-value pair that doesn't exist in the sequence. this
 // behavior is intended to handle the case that not matching element found. It's
 // not designed for this purpose. To append an element, please use ElementAppender.
 // To replace, set the key-value pair and a non-nil Element.

kyaml/yaml/fns_test.go

@@ -116,6 +116,55 @@ func TestElementSetter(t *testing.T) {
 - c: d
 `, assertNoErrorString(t)(node.String()))
 
+	node = orig.Copy()
+	// Nothing happens because no element is matched
+	rn, err = node.Pipe(ElementSetter{Key: "a", Value: "zebra"})
+	assert.NoError(t, err)
+	assert.Nil(t, rn)
+	assert.Equal(t, `- a: b
+- scalarValue
+- c: d
+`, assertNoErrorString(t)(node.String()))
+
+	node = orig.Copy()
+	// Return error because ElementSetter doesn't support a single key
+	// when there is a scalar value in the list
+	rn, err = node.Pipe(ElementSetter{Key: "a"})
+	assert.EqualError(t, err, "wrong Node Kind for  expected: MappingNode was ScalarNode: value: {scalarValue}")
+
+	node = MustParse(`
+- a: b
+- c: d	
+`)
+	// {a: b} is removed since the value is omitted and only key is used
+	// to match and no Element specified.
+	rn, err = node.Pipe(ElementSetter{Key: "a"})
+	assert.NoError(t, err)
+	assert.Nil(t, rn)
+	assert.Equal(t, `- c: d
+`, assertNoErrorString(t)(node.String()))
+
+	node = MustParse(`
+- a: b
+- c: d	
+`)
+	// Return error because ElementSetter will assume all elements are scalar when
+	// there is only value provided.
+	rn, err = node.Pipe(ElementSetter{Value: "b"})
+	assert.EqualError(t, err, "wrong Node Kind for  expected: ScalarNode was MappingNode: value: {a: b}")
+
+	node = MustParse(`
+- a
+- b
+`)
+	// b is removed since ElementSetter use the value "b" to match the
+	// scalar values.
+	rn, err = node.Pipe(ElementSetter{Value: "b"})
+	assert.NoError(t, err)
+	assert.Nil(t, rn)
+	assert.Equal(t, `- a
+`, assertNoErrorString(t)(node.String()))
+
 	node = orig.Copy()
 	// Set an element, replacing 'a: b' with 'e: f'
 	newElement := NewMapRNode(&map[string]string{