diff --git a/test/sortedIndexBy/sortedIndexBy.test.js b/test/sortedIndexBy/sortedIndexBy.test.js
index ca74bbf15..6f173a5b6 100644
--- a/test/sortedIndexBy/sortedIndexBy.test.js
+++ b/test/sortedIndexBy/sortedIndexBy.test.js
@@ -5,9 +5,10 @@ test('Testing sortedIndexBy', (t) => {
   //For more information on all the methods supported by tape
   //Please go to https://github.com/substack/tape
   t.true(typeof sortedIndexBy === 'function', 'sortedIndexBy is a Function');
+  t.equal(sortedIndexBy([{ x: 4 }, { x: 5 }], { x: 4 }, o => o.x), 0, 'Returns the lowest index to insert the element without messing up the list order');
   //t.deepEqual(sortedIndexBy(args..), 'Expected');
   //t.equal(sortedIndexBy(args..), 'Expected');
   //t.false(sortedIndexBy(args..), 'Expected');
   //t.throws(sortedIndexBy(args..), 'Expected');
   t.end();
-});
\ No newline at end of file
+});
diff --git a/test/sortedLastIndex/sortedLastIndex.test.js b/test/sortedLastIndex/sortedLastIndex.test.js
index f51f3b732..cdb77d095 100644
--- a/test/sortedLastIndex/sortedLastIndex.test.js
+++ b/test/sortedLastIndex/sortedLastIndex.test.js
@@ -5,9 +5,10 @@ test('Testing sortedLastIndex', (t) => {
   //For more information on all the methods supported by tape
   //Please go to https://github.com/substack/tape
   t.true(typeof sortedLastIndex === 'function', 'sortedLastIndex is a Function');
+  t.equal(sortedLastIndex([10, 20, 30, 30, 40], 30), 3, 'Returns the highest index to insert the element without messing up the list order');
   //t.deepEqual(sortedLastIndex(args..), 'Expected');
   //t.equal(sortedLastIndex(args..), 'Expected');
   //t.false(sortedLastIndex(args..), 'Expected');
   //t.throws(sortedLastIndex(args..), 'Expected');
   t.end();
-});
\ No newline at end of file
+});
diff --git a/test/sortedLastIndexBy/sortedLastIndexBy.test.js b/test/sortedLastIndexBy/sortedLastIndexBy.test.js
index d681fb357..e7f19f6e9 100644
--- a/test/sortedLastIndexBy/sortedLastIndexBy.test.js
+++ b/test/sortedLastIndexBy/sortedLastIndexBy.test.js
@@ -5,9 +5,10 @@ test('Testing sortedLastIndexBy', (t) => {
   //For more information on all the methods supported by tape
   //Please go to https://github.com/substack/tape
   t.true(typeof sortedLastIndexBy === 'function', 'sortedLastIndexBy is a Function');
+  t.equal(sortedLastIndexBy([{ x: 4 }, { x: 5 }], { x: 4 }, o => o.x), 1, 'Returns the highest index to insert the element without messing up the list order');
   //t.deepEqual(sortedLastIndexBy(args..), 'Expected');
   //t.equal(sortedLastIndexBy(args..), 'Expected');
   //t.false(sortedLastIndexBy(args..), 'Expected');
   //t.throws(sortedLastIndexBy(args..), 'Expected');
   t.end();
-});
\ No newline at end of file
+});
diff --git a/test/testlog b/test/testlog
index 4fcedcdc1..038c55e6b 100644
--- a/test/testlog
+++ b/test/testlog
@@ -1,4 +1,4 @@
-Test log for: Sat Feb 03 2018 12:21:49 GMT+0200 (GTB Standard Time)
+Test log for: Sat Feb 03 2018 12:25:38 GMT+0200 (GTB Standard Time)
 
 > 30-seconds-of-code@0.0.1 test G:\My Files\git Repositories\30-seconds-of-code
 > tape test/**/*.test.js | tap-spec
@@ -1263,14 +1263,17 @@ Test log for: Sat Feb 03 2018 12:21:49 GMT+0200 (GTB Standard Time)
   Testing sortedIndexBy
 
     √ sortedIndexBy is a Function
+    √ Returns the lowest index to insert the element without messing up the list order
 
   Testing sortedLastIndex
 
     √ sortedLastIndex is a Function
+    √ Returns the highest index to insert the element without messing up the list order
 
   Testing sortedLastIndexBy
 
     √ sortedLastIndexBy is a Function
+    √ Returns the highest index to insert the element without messing up the list order
 
   Testing speechSynthesis
 
@@ -1642,8 +1645,8 @@ Test log for: Sat Feb 03 2018 12:21:49 GMT+0200 (GTB Standard Time)
     √ Works with multiple promises
 
 
-  total:     746
-  passing:   746
+  total:     749
+  passing:   749
   duration:  2.4s