diff --git a/CoreStoreTests/BaseTests/BaseTestCase.swift b/CoreStoreTests/BaseTests/BaseTestCase.swift
index f0edb87..305e6c3 100644
--- a/CoreStoreTests/BaseTests/BaseTestCase.swift
+++ b/CoreStoreTests/BaseTests/BaseTestCase.swift
@@ -71,7 +71,7 @@ class BaseTestCase: XCTestCase {
         defer {
             
             self.waitForExpectationsWithTimeout(0, handler: nil)
-            CoreStore.logger = DefaultLogger()
+            CoreStore.logger = TestLogger([:])
         }
         return closure()
     }
diff --git a/CoreStoreTests/FetchTests.swift b/CoreStoreTests/FetchTests.swift
index 3dd970d..8c2bdc6 100644
--- a/CoreStoreTests/FetchTests.swift
+++ b/CoreStoreTests/FetchTests.swift
@@ -144,7 +144,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(object)
                     
-                    let objectID = stack.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
                 do {
@@ -153,10 +156,16 @@ final class FetchTests: BaseTestDataTestCase {
                         Where("%K < %@", "testNumber", 4),
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let object = stack.fetchOne(from, fetchClauses)
+                    let object = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchOne(from, fetchClauses)
+                    }
                     XCTAssertNil(object)
                     
-                    let objectID = stack.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
             }
@@ -318,7 +327,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(object)
                     
-                    let objectID = stack.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
                 do {
@@ -327,10 +339,16 @@ final class FetchTests: BaseTestDataTestCase {
                         Where("%K < %@", "testNumber", 4),
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let object = stack.fetchOne(from, fetchClauses)
+                    let object = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchOne(from, fetchClauses)
+                    }
                     XCTAssertNil(object)
                     
-                    let objectID = stack.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
             }
@@ -643,7 +661,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = stack.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
                 do {
@@ -652,10 +673,16 @@ final class FetchTests: BaseTestDataTestCase {
                         Where("testNumber", isEqualTo: 0),
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let objects = stack.fetchAll(from, fetchClauses)
+                    let objects = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchAll(from, fetchClauses)
+                    }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = stack.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
             }
@@ -884,7 +911,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = stack.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
                 do {
@@ -892,10 +922,16 @@ final class FetchTests: BaseTestDataTestCase {
                     let fetchClauses: [FetchClause] = [
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let objects = stack.fetchAll(from, fetchClauses)
+                    let objects = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchAll(from, fetchClauses)
+                    }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = stack.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
             }
@@ -1210,11 +1246,14 @@ final class FetchTests: BaseTestDataTestCase {
                 }
                 do {
                     
-                    let count = stack.fetchCount(
-                        from,
-                        Where("testNumber", isEqualTo: 0),
-                        OrderBy(.Descending("testEntityID"))
-                    )
+                    let count = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchCount(
+                            from,
+                            Where("testNumber", isEqualTo: 0),
+                            OrderBy(.Descending("testEntityID"))
+                        )
+                    }
                     XCTAssertNil(count)
                 }
             }
@@ -1354,11 +1393,14 @@ final class FetchTests: BaseTestDataTestCase {
                 }
                 do {
                     
-                    let count = stack.fetchCount(
-                        from,
-                        Where("testNumber", isEqualTo: 0),
-                        OrderBy(.Descending("testEntityID"))
-                    )
+                    let count = self.expectLogger([.LogWarning]) {
+                        
+                        stack.fetchCount(
+                            from,
+                            Where("testNumber", isEqualTo: 0),
+                            OrderBy(.Descending("testEntityID"))
+                        )
+                    }
                     XCTAssertNil(count)
                 }
             }
@@ -1595,7 +1637,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(object)
                     
-                    let objectID = transaction.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
                 do {
@@ -1604,10 +1649,16 @@ final class FetchTests: BaseTestDataTestCase {
                         Where("%K < %@", "testNumber", 4),
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let object = transaction.fetchOne(from, fetchClauses)
+                    let object = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchOne(from, fetchClauses)
+                    }
                     XCTAssertNil(object)
                     
-                    let objectID = transaction.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
             }
@@ -1769,7 +1820,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(object)
                     
-                    let objectID = transaction.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
                 do {
@@ -1778,10 +1832,16 @@ final class FetchTests: BaseTestDataTestCase {
                         Where("%K < %@", "testNumber", 4),
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let object = transaction.fetchOne(from, fetchClauses)
+                    let object = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchOne(from, fetchClauses)
+                    }
                     XCTAssertNil(object)
                     
-                    let objectID = transaction.fetchObjectID(from, fetchClauses)
+                    let objectID = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectID(from, fetchClauses)
+                    }
                     XCTAssertNil(objectID)
                 }
             }
@@ -2094,7 +2154,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = transaction.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
                 do {
@@ -2103,10 +2166,16 @@ final class FetchTests: BaseTestDataTestCase {
                         Where("testNumber", isEqualTo: 0),
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let objects = transaction.fetchAll(from, fetchClauses)
+                    let objects = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchAll(from, fetchClauses)
+                    }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = transaction.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
             }
@@ -2335,7 +2404,10 @@ final class FetchTests: BaseTestDataTestCase {
                     }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = transaction.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
                 do {
@@ -2343,10 +2415,16 @@ final class FetchTests: BaseTestDataTestCase {
                     let fetchClauses: [FetchClause] = [
                         OrderBy(.Descending("testEntityID"))
                     ]
-                    let objects = transaction.fetchAll(from, fetchClauses)
+                    let objects = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchAll(from, fetchClauses)
+                    }
                     XCTAssertNil(objects)
                     
-                    let objectIDs = transaction.fetchObjectIDs(from, fetchClauses)
+                    let objectIDs = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchObjectIDs(from, fetchClauses)
+                    }
                     XCTAssertNil(objectIDs)
                 }
             }
@@ -2661,11 +2739,14 @@ final class FetchTests: BaseTestDataTestCase {
                 }
                 do {
                     
-                    let count = transaction.fetchCount(
-                        from,
-                        Where("testNumber", isEqualTo: 0),
-                        OrderBy(.Descending("testEntityID"))
-                    )
+                    let count = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchCount(
+                            from,
+                            Where("testNumber", isEqualTo: 0),
+                            OrderBy(.Descending("testEntityID"))
+                        )
+                    }
                     XCTAssertNil(count)
                 }
             }
@@ -2805,11 +2886,14 @@ final class FetchTests: BaseTestDataTestCase {
                 }
                 do {
                     
-                    let count = transaction.fetchCount(
-                        from,
-                        Where("testNumber", isEqualTo: 0),
-                        OrderBy(.Descending("testEntityID"))
-                    )
+                    let count = self.expectLogger([.LogWarning]) {
+                        
+                        transaction.fetchCount(
+                            from,
+                            Where("testNumber", isEqualTo: 0),
+                            OrderBy(.Descending("testEntityID"))
+                        )
+                    }
                     XCTAssertNil(count)
                 }
             }
diff --git a/CoreStoreTests/FromTests.swift b/CoreStoreTests/FromTests.swift
index 7ba6802..a94f5fa 100644
--- a/CoreStoreTests/FromTests.swift
+++ b/CoreStoreTests/FromTests.swift
@@ -174,7 +174,10 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>()
                 
                 let request = NSFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
+                let storesFound = self.expectLogger([.LogWarning]) {
+                    
+                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                }
                 XCTAssertFalse(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.affectedStores)
@@ -189,7 +192,10 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config1")
                 
                 let request = NSFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
+                let storesFound = self.expectLogger([.LogWarning]) {
+                    
+                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                }
                 XCTAssertFalse(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.affectedStores)
@@ -204,7 +210,10 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config2")
                 
                 let request = NSFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
+                let storesFound = self.expectLogger([.LogWarning]) {
+                    
+                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                }
                 XCTAssertFalse(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.affectedStores)
@@ -290,7 +299,10 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config1")
                 
                 let request = NSFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
+                let storesFound = self.expectLogger([.LogWarning]) {
+                    
+                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                }
                 XCTAssertFalse(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.affectedStores)
@@ -305,7 +317,10 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config2")
                 
                 let request = NSFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
+                let storesFound = self.expectLogger([.LogWarning]) {
+                    
+                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                }
                 XCTAssertFalse(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.affectedStores)
@@ -391,7 +406,10 @@ final class FromTests: BaseTestCase {
                 let from = From<TestEntity2>("Config1")
                 
                 let request = NSFetchRequest()
-                let storesFound = from.applyToFetchRequest(request, context: dataStack.mainContext)
+                let storesFound = self.expectLogger([.LogWarning]) {
+                    
+                    from.applyToFetchRequest(request, context: dataStack.mainContext)
+                }
                 XCTAssertFalse(storesFound)
                 XCTAssertNotNil(request.entity)
                 XCTAssertNotNil(request.affectedStores)
diff --git a/CoreStoreTests/Model.xcdatamodeld/Model.xcdatamodel/contents b/CoreStoreTests/Model.xcdatamodeld/Model.xcdatamodel/contents
index a32a044..900d3c5 100644
--- a/CoreStoreTests/Model.xcdatamodeld/Model.xcdatamodel/contents
+++ b/CoreStoreTests/Model.xcdatamodeld/Model.xcdatamodel/contents
@@ -6,6 +6,7 @@
         <attribute name="testDate" optional="YES" attributeType="Date" syncable="YES"/>
         <attribute name="testDecimal" optional="YES" attributeType="Decimal" defaultValueString="0.0" syncable="YES"/>
         <attribute name="testEntityID" attributeType="Integer 64" syncable="YES"/>
+        <attribute name="testNil" optional="YES" attributeType="String" syncable="YES"/>
         <attribute name="testNumber" optional="YES" attributeType="Integer 32" defaultValueString="0" syncable="YES"/>
         <attribute name="testString" optional="YES" attributeType="String" syncable="YES"/>
     </entity>
@@ -15,6 +16,7 @@
         <attribute name="testDate" optional="YES" attributeType="Date" syncable="YES"/>
         <attribute name="testDecimal" optional="YES" attributeType="Decimal" defaultValueString="0.0" syncable="YES"/>
         <attribute name="testEntityID" attributeType="Integer 64" syncable="YES"/>
+        <attribute name="testNil" optional="YES" attributeType="String" syncable="YES"/>
         <attribute name="testNumber" optional="YES" attributeType="Integer 32" defaultValueString="0" syncable="YES"/>
         <attribute name="testString" optional="YES" attributeType="String" syncable="YES"/>
     </entity>
@@ -25,7 +27,7 @@
         <memberEntity name="TestEntity2"/>
     </configuration>
     <elements>
-        <element name="TestEntity1AAA" positionX="-63" positionY="-18" width="128" height="150"/>
-        <element name="TestEntity2" positionX="-63" positionY="9" width="128" height="150"/>
+        <element name="TestEntity1AAA" positionX="-63" positionY="-18" width="128" height="165"/>
+        <element name="TestEntity2" positionX="-63" positionY="9" width="128" height="165"/>
     </elements>
 </model>
\ No newline at end of file
diff --git a/CoreStoreTests/QueryTests.swift b/CoreStoreTests/QueryTests.swift
index 052b23b..cae3d43 100644
--- a/CoreStoreTests/QueryTests.swift
+++ b/CoreStoreTests/QueryTests.swift
@@ -1153,4 +1153,125 @@ class QueryTests: BaseTestDataTestCase {
             }
         }
     }
+    
+    @objc
+    dynamic func test_ThatDataStacks_CanQueryAttributes() {
+        
+        let configurations: [String?] = [nil]
+        self.prepareStack(configurations: configurations) { (stack) in
+            
+            self.prepareTestDataForStack(stack, configurations: configurations)
+            
+            let from = From<TestEntity1>(configurations)
+            let queryClauses: [QueryClause] = [
+                Where("%K > %@", "testNumber", 3),
+                OrderBy(.Ascending("testEntityID"))
+            ]
+            do {
+                
+                let values = stack.queryAttributes(
+                    from,
+                    Select(
+                        "testBoolean",
+                        "testNumber",
+                        "testDecimal",
+                        "testString",
+                        "testData",
+                        "testDate",
+                        "testNil"
+                    ),
+                    queryClauses
+                )
+                XCTAssertNotNil(values)
+                XCTAssertEqual(
+                    values!,
+                    [
+                        [
+                            "testBoolean": NSNumber(bool: false),
+                            "testNumber": NSNumber(integer: 4),
+                            "testDecimal": NSDecimalNumber(string: "4"),
+                            "testString": "nil:TestEntity1:4",
+                            "testData": ("nil:TestEntity1:4" as NSString).dataUsingEncoding(NSUTF8StringEncoding)!,
+                            "testDate": self.dateFormatter.dateFromString("2000-01-04T00:00:00Z")!
+                        ],
+                        [
+                            "testBoolean": NSNumber(bool: true),
+                            "testNumber": NSNumber(integer: 5),
+                            "testDecimal": NSDecimalNumber(string: "5"),
+                            "testString": "nil:TestEntity1:5",
+                            "testData": ("nil:TestEntity1:5" as NSString).dataUsingEncoding(NSUTF8StringEncoding)!,
+                            "testDate": self.dateFormatter.dateFromString("2000-01-05T00:00:00Z")!
+                        ]
+                    ]
+                )
+            }
+        }
+    }
+    
+    @objc
+    dynamic func test_ThatDataStacks_CanQueryAggregates() {
+        
+        let configurations: [String?] = [nil]
+        self.prepareStack(configurations: configurations) { (stack) in
+            
+            self.prepareTestDataForStack(stack, configurations: configurations)
+            
+            let from = From<TestEntity1>(configurations)
+            let queryClauses: [QueryClause] = []
+            do {
+                
+                let values = stack.queryAttributes(
+                    from,
+                    Select(
+                        .Sum("testBoolean"),
+                        .Count("testNumber"),
+                        .Maximum("testNumber"),
+                        .Minimum("testNumber"),
+                        .Average("testDecimal")
+                    ),
+                    queryClauses
+                )
+                XCTAssertNotNil(values)
+                XCTAssertEqual(
+                    values!,
+                    [
+                        [
+                            "sum(testBoolean)": 3,
+                            "count(testNumber)": 5,
+                            "max(testNumber)": 5,
+                            "min(testNumber)": 1,
+                            "average(testDecimal)": 3,
+                        ]
+                    ]
+                )
+            }
+            do {
+                
+                let values = stack.queryAttributes(
+                    from,
+                    Select(
+                        .Sum("testBoolean", As: "testSum"),
+                        .Count("testNumber", As: "testCount"),
+                        .Maximum("testNumber", As: "testMaximum"),
+                        .Minimum("testNumber", As: "testMinimum"),
+                        .Average("testDecimal", As: "testAverage")
+                    ),
+                    queryClauses
+                )
+                XCTAssertNotNil(values)
+                XCTAssertEqual(
+                    values!,
+                    [
+                        [
+                            "testSum": 3,
+                            "testCount": 5,
+                            "testMaximum": 5,
+                            "testMinimum": 1,
+                            "testAverage": 3,
+                        ]
+                    ]
+                )
+            }
+        }
+    }
 }
diff --git a/CoreStoreTests/TestEntities/TestEntity1.swift b/CoreStoreTests/TestEntities/TestEntity1.swift
index a8c200d..8f5c302 100644
--- a/CoreStoreTests/TestEntities/TestEntity1.swift
+++ b/CoreStoreTests/TestEntities/TestEntity1.swift
@@ -35,4 +35,5 @@ class TestEntity1: NSManagedObject {
     @NSManaged var testBoolean: NSNumber?
     @NSManaged var testDecimal: NSDecimalNumber?
     @NSManaged var testData: NSData?
+    @NSManaged var testNil: String?
 }
diff --git a/CoreStoreTests/TestEntities/TestEntity2.swift b/CoreStoreTests/TestEntities/TestEntity2.swift
index 50739d0..3919646 100644
--- a/CoreStoreTests/TestEntities/TestEntity2.swift
+++ b/CoreStoreTests/TestEntities/TestEntity2.swift
@@ -35,4 +35,5 @@ class TestEntity2: NSManagedObject {
     @NSManaged var testBoolean: NSNumber?
     @NSManaged var testDecimal: NSDecimalNumber?
     @NSManaged var testData: NSData?
+    @NSManaged var testNil: String?
 }