diff --git a/.gitignore b/.gitignore
index 2f5858d63..57321f776 100644
--- a/.gitignore
+++ b/.gitignore
@@ -46,3 +46,6 @@ Resources/WebDriverAgent.bundle
 
 # Modules map recreated on each build
 Modules/module.modulemap
+
+# test run
+*.trace
diff --git a/WebDriverAgentLib/Categories/NSExpression+FBFormat.m b/WebDriverAgentLib/Categories/NSExpression+FBFormat.m
index f5d51d8e6..fa5d8e3c3 100644
--- a/WebDriverAgentLib/Categories/NSExpression+FBFormat.m
+++ b/WebDriverAgentLib/Categories/NSExpression+FBFormat.m
@@ -17,14 +17,14 @@ + (instancetype)fb_wdExpressionWithExpression:(NSExpression *)input
   if ([input expressionType] != NSKeyPathExpressionType) {
     return input;
   }
-  NSString *actualPropName = [input keyPath];
-  NSUInteger dotPos = [actualPropName rangeOfString:@"."].location;
+  NSString *propName = [input keyPath];
+  NSUInteger dotPos = [propName rangeOfString:@"."].location;
   if (NSNotFound != dotPos) {
-    actualPropName = [actualPropName substringToIndex:dotPos];
-    NSString *suffix = [actualPropName substringFromIndex:dotPos];
+    NSString *actualPropName = [propName substringToIndex:dotPos];
+    NSString *suffix = [propName substringFromIndex:(dotPos + 1)];
     return [NSExpression expressionForKeyPath:[NSString stringWithFormat:@"%@.%@", [FBElementUtils wdAttributeNameForAttributeName:actualPropName], suffix]];
   }
-  return [NSExpression expressionForKeyPath:[FBElementUtils wdAttributeNameForAttributeName:actualPropName]];
+  return [NSExpression expressionForKeyPath:[FBElementUtils wdAttributeNameForAttributeName:propName]];
 }
 
 @end
diff --git a/WebDriverAgentTests/UnitTests/NSExpressionFBFormatTests.m b/WebDriverAgentTests/UnitTests/NSExpressionFBFormatTests.m
index 67e6d14b6..e590dab2d 100644
--- a/WebDriverAgentTests/UnitTests/NSExpressionFBFormatTests.m
+++ b/WebDriverAgentTests/UnitTests/NSExpressionFBFormatTests.m
@@ -20,31 +20,36 @@ @implementation NSExpressionFBFormatTests
 - (void)testFormattingForExistingProperty
 {
   NSExpression *expr = [NSExpression expressionWithFormat:@"wdName"];
-  XCTAssertNotNil([NSExpression fb_wdExpressionWithExpression:expr]);
+  NSExpression *prop = [NSExpression fb_wdExpressionWithExpression:expr];
+  XCTAssertEqualObjects([prop keyPath], @"wdName");
 }
 
 - (void)testFormattingForExistingPropertyShortcut
 {
   NSExpression *expr = [NSExpression expressionWithFormat:@"visible"];
-  XCTAssertNotNil([NSExpression fb_wdExpressionWithExpression:expr]);
+  NSExpression *prop = [NSExpression fb_wdExpressionWithExpression:expr];
+  XCTAssertEqualObjects([prop keyPath], @"isWDVisible");
 }
 
 - (void)testFormattingForValidExpressionWOKeys
 {
   NSExpression *expr = [NSExpression expressionWithFormat:@"1"];
-  XCTAssertNotNil([NSExpression fb_wdExpressionWithExpression:expr]);
+  NSExpression *prop = [NSExpression fb_wdExpressionWithExpression:expr];
+  XCTAssertEqualObjects([prop constantValue], [NSNumber numberWithInt:1]);
 }
 
 - (void)testFormattingForExistingComplexProperty
 {
   NSExpression *expr = [NSExpression expressionWithFormat:@"wdRect.x"];
-  XCTAssertNotNil([NSExpression fb_wdExpressionWithExpression:expr]);
+  NSExpression *prop = [NSExpression fb_wdExpressionWithExpression:expr];
+  XCTAssertEqualObjects([prop keyPath], @"wdRect.x");
 }
 
 - (void)testFormattingForExistingComplexPropertyWOPrefix
 {
   NSExpression *expr = [NSExpression expressionWithFormat:@"rect.x"];
-  XCTAssertNotNil([NSExpression fb_wdExpressionWithExpression:expr]);
+  NSExpression *prop = [NSExpression fb_wdExpressionWithExpression:expr];
+  XCTAssertEqualObjects([prop keyPath], @"wdRect.x");
 }
 
 - (void)testFormattingForPredicateWithUnknownKey