1 files changed, 38 insertions, 6 deletions

diff --git a/test/unit/tx-utils-test.js b/test/unit/tx-utils-test.js
index 65233e1d9..e57b25e83 100644
--- a/test/unit/tx-utils-test.js
+++ b/test/unit/tx-utils-test.js
@@ -13,14 +13,46 @@ describe('txUtils', function() {
   })
 
   describe('addGasBuffer', function() {
-    it('multiplies by 1.5', function() {
-      const input = '0x123fad'
-      const output = txUtils.addGasBuffer(input, '0x3d4c52') //0x3d4c52 is 4mil for dummy gas limit
-
-      const inputBn = new BN(ethUtil.stripHexPrefix(input), 'hex')
-      const outputBn = new BN(ethUtil.stripHexPrefix(output), 'hex')
+    it('multiplies by 1.5, when within block gas limit', function() {
+      // naive estimatedGas: 0x123fad (~1.2 mil)
+      const inputHex = '0x123fad'
+      // dummy gas limit: 0x3d4c52 (4 mil)
+      const blockGasLimitHex = '0x3d4c52'
+      const output = txUtils.addGasBuffer(inputHex, blockGasLimitHex)
+      const inputBn = hexToBn(inputHex)
+      const outputBn = hexToBn(output)
       const expectedBn = inputBn.muln(1.5)
       assert(outputBn.eq(expectedBn), 'returns 1.5 the input value')
     })
+    
+    it('uses original estimatedGas, when above block gas limit', function() {
+      // naive estimatedGas: 0x123fad (~1.2 mil)
+      const inputHex = '0x123fad'
+      // dummy gas limit: 0x0f4240 (1 mil)
+      const blockGasLimitHex = '0x0f4240'
+      const output = txUtils.addGasBuffer(inputHex, blockGasLimitHex)
+      const inputBn = hexToBn(inputHex)
+      const outputBn = hexToBn(output)
+      const expectedBn = hexToBn(inputHex)
+      assert(outputBn.eq(expectedBn), 'returns the original estimatedGas value')
+    })
+
+    it('buffers up to block gas limit', function() {
+      // naive estimatedGas: 0x123fad (~1.2 mil)
+      const inputHex = '0x1e8480'
+      // dummy gas limit: 0x1e8480 (2 mil)
+      const blockGasLimitHex = '0x1e8480'
+      const output = txUtils.addGasBuffer(inputHex, blockGasLimitHex)
+      const inputBn = hexToBn(inputHex)
+      const outputBn = hexToBn(output)
+      const expectedBn = hexToBn(blockGasLimitHex)
+      assert(outputBn.eq(expectedBn), 'returns the block gas limit value')
+    })
   })
 })
+
+// util
+
+function hexToBn(inputHex) {
+  return new BN(ethUtil.stripHexPrefix(inputHex), 16)
+}
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