diff --git a/test/ecpair.js b/test/ecpair.js
index 0e9a3a1..127aa02 100644
--- a/test/ecpair.js
+++ b/test/ecpair.js
@@ -165,12 +165,21 @@ describe('ECPair', function () {
       assert.strictEqual(keyPair.network, NETWORKS.testnet)
     })
 
-    it('loops until d is within interval [1, n - 1]', sinon.test(function () {
+    it('loops until d is within interval [1, n - 1] : 1', sinon.test(function () {
+      var rng = this.mock()
+      rng.exactly(2)
+      rng.onCall(0).returns(BigInteger.ZERO.toBuffer(32)) // invalid length
+      rng.onCall(1).returns(BigInteger.ONE.toBuffer(32)) // === 1
+
+      ECPair.makeRandom({ rng: rng })
+    }))
+
+    it('loops until d is within interval [1, n - 1] : n - 1', sinon.test(function () {
       var rng = this.mock()
       rng.exactly(3)
-      rng.onCall(0).returns(new BigInteger('0').toBuffer(32)) // < 1
+      rng.onCall(0).returns(BigInteger.ZERO.toBuffer(32)) // < 1
       rng.onCall(1).returns(curve.n.toBuffer(32)) // > n-1
-      rng.onCall(2).returns(new BigInteger('42').toBuffer(32)) // valid
+      rng.onCall(2).returns(curve.n.subtract(BigInteger.ONE).toBuffer(32)) // === n-1
 
       ECPair.makeRandom({ rng: rng })
     }))