diff --git a/test/language/expressions/postfix-decrement/bigint.js b/test/language/expressions/postfix-decrement/bigint.js
new file mode 100644
index 0000000000000000000000000000000000000000..684c67d7315f68e70f05def3830f162f31138388
--- /dev/null
+++ b/test/language/expressions/postfix-decrement/bigint.js
@@ -0,0 +1,63 @@
+// Copyright (C) 2017 Josh Wolfe. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Postfix decrement for references to BigInt values
+esid: sec-postfix-decrement-operator-runtime-semantics-evaluation
+info: |
+  1. Let expr be the result of evaluating UnaryExpression.
+  2. Let oldValue be ? ToNumeric(? GetValue(expr)).
+  3. Let newValue be ? Type(oldvalue)::subtract(oldValue, Type(oldValue)::unit).
+  4. Perform ? PutValue(expr, newValue).
+  5. Return oldValue. 
+
+features: [BigInt]
+---*/
+
+var x = 1n;
+assert.sameValue(x--, 1n, "var x = 1n; x-- === 1n");
+assert.sameValue(x, 0n, "var x = 1n; x--; x === 0n");
+
+var x = 0n;
+assert.sameValue(x--, 0n, "var x = 0n; x-- === 0n");
+assert.sameValue(x, -1n, "var x = 0n; x--; x === -1n");
+
+var x = 123457n;
+assert.sameValue(x--, 123457n, "var x = 123457n; x-- === 123457n");
+assert.sameValue(x, 123456n, "var x = 123457n; x--; x === 123456n");
+
+var x = -123456n;
+assert.sameValue(x--, -123456n, "var x = -123456n; x-- === -123456n");
+assert.sameValue(x, -123457n, "var x = -123456n; x--; x === -123457n");
+
+var x = 0x1fffffffffffff01n;
+assert.sameValue(x--, 0x1fffffffffffff01n, "var x = 0x1fffffffffffff01n; x-- === 0x1fffffffffffff01n");
+assert.sameValue(x, 0x1fffffffffffff00n, "var x = 0x1fffffffffffff01n; x--; x === 0x1fffffffffffff00n");
+
+var x = -0x1fffffffffffff00n;
+assert.sameValue(x--, -0x1fffffffffffff00n, "var x = -0x1fffffffffffff00n; x-- === -0x1fffffffffffff00n");
+assert.sameValue(x, -0x1fffffffffffff01n, "var x = -0x1fffffffffffff00n; x--; x === -0x1fffffffffffff01n");
+
+var x = {y:1n};
+assert.sameValue(x.y--, 1n, "var x = {y:1n}; x.y-- === 1n");
+assert.sameValue(x.y, 0n, "var x = {y:1n}; x.y--; x.y === 0n");
+
+var x = {y:{z:1n}};
+assert.sameValue(x.y.z--, 1n, "var x = {y:{z:1n}}; x.y.z-- === 1n");
+assert.sameValue(x.y.z, 0n, "var x = {y:{z:1n}}; x.y.z--; x.y.z === 0n");
+
+var x = [1n];
+assert.sameValue(x[0]--, 1n, "var x = [1n]; x[0]-- === 1n");
+assert.sameValue(x[0], 0n, "var x = [1n]; x[0]--; x[0] === 0n");
+
+var x = [null, [null, null, 1n]];
+assert.sameValue(x[1][2]--, 1n, "var x = [null, [null, null, 1n]]; x[1][2]-- === 1n");
+assert.sameValue(x[1][2], 0n, "var x = [null, [null, null, 1n]]; x[1][2]--; x[1][2] === 0n");
+
+var x = {y:[1n]};
+assert.sameValue(x.y[0]--, 1n, "var x = {y:[1n]}; x.y[0]-- === 1n");
+assert.sameValue(x.y[0], 0n, "var x = {y:[1n]}; x.y[0]--; x.y[0] === 0n");
+
+var x = [{z:1n}];
+assert.sameValue(x[0].z--, 1n, "var x = [{z:1n}]; x[0].z-- === 1n");
+assert.sameValue(x[0].z, 0n, "var x = [{z:1n}]; x[0].z--; x[0].z === 0n");
diff --git a/test/language/expressions/postfix-increment/bigint.js b/test/language/expressions/postfix-increment/bigint.js
new file mode 100644
index 0000000000000000000000000000000000000000..76d83f03b9d8acb99cb7d4085a881d1adb7ae4a0
--- /dev/null
+++ b/test/language/expressions/postfix-increment/bigint.js
@@ -0,0 +1,63 @@
+// Copyright (C) 2017 Josh Wolfe. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Postfix increment for references to BigInt values
+esid: sec-postfix-increment-operator-runtime-semantics-evaluation
+info: |
+  1. Let expr be the result of evaluating UnaryExpression.
+  2. Let oldValue be ? ToNumeric(? GetValue(expr)).
+  3. Let newValue be ? Type(oldvalue)::add(oldValue, Type(oldValue)::unit).
+  4. Perform ? PutValue(expr, newValue).
+  5. Return oldValue. 
+
+features: [BigInt]
+---*/
+
+var x = 0n;
+assert.sameValue(x++, 0n, "var x = 0n; x++ === 0n");
+assert.sameValue(x, 1n, "var x = 0n; x++; x === 1n");
+
+var x = -1n;
+assert.sameValue(x++, -1n, "var x = -1n; x++ === -1n");
+assert.sameValue(x, 0n, "var x = -1n; x++; x === 0n");
+
+var x = 123456n;
+assert.sameValue(x++, 123456n, "var x = 123456n; x++ === 123456n");
+assert.sameValue(x, 123457n, "var x = 123456n; x++; x === 123457n");
+
+var x = -123457n;
+assert.sameValue(x++, -123457n, "var x = -123457n; x++ === -123457n");
+assert.sameValue(x, -123456n, "var x = -123457n; x++; x === -123456n");
+
+var x = 0x1fffffffffffff00n;
+assert.sameValue(x++, 0x1fffffffffffff00n, "var x = 0x1fffffffffffff00n; x++ === 0x1fffffffffffff00n");
+assert.sameValue(x, 0x1fffffffffffff01n, "var x = 0x1fffffffffffff00n; x++; x === 0x1fffffffffffff01n");
+
+var x = -0x1fffffffffffff01n;
+assert.sameValue(x++, -0x1fffffffffffff01n, "var x = -0x1fffffffffffff01n; x++ === -0x1fffffffffffff01n");
+assert.sameValue(x, -0x1fffffffffffff00n, "var x = -0x1fffffffffffff01n; x++; x === -0x1fffffffffffff00n");
+
+var x = {y:0n};
+assert.sameValue(x.y++, 0n, "var x = {y:0n}; x.y++ === 0n");
+assert.sameValue(x.y, 1n, "var x = {y:0n}; x.y++; x.y === 1n");
+
+var x = {y:{z:0n}};
+assert.sameValue(x.y.z++, 0n, "var x = {y:{z:0n}}; x.y.z++ === 0n");
+assert.sameValue(x.y.z, 1n, "var x = {y:{z:0n}}; x.y.z++; x.y.z === 1n");
+
+var x = [0n];
+assert.sameValue(x[0]++, 0n, "var x = [0n]; x[0]++ === 0n");
+assert.sameValue(x[0], 1n, "var x = [0n]; x[0]++; x[0] === 1n");
+
+var x = [null, [null, null, 0n]];
+assert.sameValue(x[1][2]++, 0n, "var x = [null, [null, null, 0n]]; x[1][2]++ === 0n");
+assert.sameValue(x[1][2], 1n, "var x = [null, [null, null, 0n]]; x[1][2]++; x[1][2] === 1n");
+
+var x = {y:[0n]};
+assert.sameValue(x.y[0]++, 0n, "var x = {y:[0n]}; x.y[0]++ === 0n");
+assert.sameValue(x.y[0], 1n, "var x = {y:[0n]}; x.y[0]++; x.y[0] === 1n");
+
+var x = [{z:0n}];
+assert.sameValue(x[0].z++, 0n, "var x = [{z:0n}]; x[0].z++ === 0n");
+assert.sameValue(x[0].z, 1n, "var x = [{z:0n}]; x[0].z++; x[0].z === 1n");
diff --git a/test/language/expressions/prefix-decrement/bigint.js b/test/language/expressions/prefix-decrement/bigint.js
new file mode 100644
index 0000000000000000000000000000000000000000..fe20da0a05e433a2c58add707247afc80d13940e
--- /dev/null
+++ b/test/language/expressions/prefix-decrement/bigint.js
@@ -0,0 +1,63 @@
+// Copyright (C) 2017 Josh Wolfe. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Prefix decrement for references to BigInt values
+esid: sec-prefix-decrement-operator-runtime-semantics-evaluation
+info: |
+  1. Let expr be the result of evaluating UnaryExpression.
+  2. Let oldValue be ? ToNumeric(? GetValue(expr)).
+  3. Let newValue be ? Type(oldvalue)::subtract(oldValue, Type(oldValue)::unit).
+  4. Perform ? PutValue(expr, newValue).
+  5. Return newValue. 
+
+features: [BigInt]
+---*/
+
+var x = 1n;
+assert.sameValue(--x, 0n, "var x = 1n; --x === 0n");
+assert.sameValue(x, 0n, "var x = 1n; --x; x === 0n");
+
+var x = 0n;
+assert.sameValue(--x, -1n, "var x = 0n; --x === -1n");
+assert.sameValue(x, -1n, "var x = 0n; --x; x === -1n");
+
+var x = 123457n;
+assert.sameValue(--x, 123456n, "var x = 123457n; --x === 123456n");
+assert.sameValue(x, 123456n, "var x = 123457n; --x; x === 123456n");
+
+var x = -123456n;
+assert.sameValue(--x, -123457n, "var x = -123456n; --x === -123457n");
+assert.sameValue(x, -123457n, "var x = -123456n; --x; x === -123457n");
+
+var x = 0x1fffffffffffff01n;
+assert.sameValue(--x, 0x1fffffffffffff00n, "var x = 0x1fffffffffffff01n; --x === 0x1fffffffffffff00n");
+assert.sameValue(x, 0x1fffffffffffff00n, "var x = 0x1fffffffffffff01n; --x; x === 0x1fffffffffffff00n");
+
+var x = -0x1fffffffffffff00n;
+assert.sameValue(--x, -0x1fffffffffffff01n, "var x = -0x1fffffffffffff00n; --x === -0x1fffffffffffff01n");
+assert.sameValue(x, -0x1fffffffffffff01n, "var x = -0x1fffffffffffff00n; --x; x === -0x1fffffffffffff01n");
+
+var x = {y:1n};
+assert.sameValue(--x.y, 0n, "var x = {y:1n}; --x.y === 0n");
+assert.sameValue(x.y, 0n, "var x = {y:1n}; --x.y; x.y === 0n");
+
+var x = {y:{z:1n}};
+assert.sameValue(--x.y.z, 0n, "var x = {y:{z:1n}}; --x.y.z === 0n");
+assert.sameValue(x.y.z, 0n, "var x = {y:{z:1n}}; --x.y.z; x.y.z === 0n");
+
+var x = [1n];
+assert.sameValue(--x[0], 0n, "var x = [1n]; --x[0] === 0n");
+assert.sameValue(x[0], 0n, "var x = [1n]; --x[0]; x[0] === 0n");
+
+var x = [null, [null, null, 1n]];
+assert.sameValue(--x[1][2], 0n, "var x = [null, [null, null, 1n]]; --x[1][2] === 0n");
+assert.sameValue(x[1][2], 0n, "var x = [null, [null, null, 1n]]; --x[1][2]; x[1][2] === 0n");
+
+var x = {y:[1n]};
+assert.sameValue(--x.y[0], 0n, "var x = {y:[1n]}; --x.y[0] === 0n");
+assert.sameValue(x.y[0], 0n, "var x = {y:[1n]}; --x.y[0]; x.y[0] === 0n");
+
+var x = [{z:1n}];
+assert.sameValue(--x[0].z, 0n, "var x = [{z:1n}]; --x[0].z === 0n");
+assert.sameValue(x[0].z, 0n, "var x = [{z:1n}]; --x[0].z; x[0].z === 0n");
diff --git a/test/language/expressions/prefix-increment/bigint.js b/test/language/expressions/prefix-increment/bigint.js
new file mode 100644
index 0000000000000000000000000000000000000000..47bee678973948f4b7ab79ca8a84b17785a67d41
--- /dev/null
+++ b/test/language/expressions/prefix-increment/bigint.js
@@ -0,0 +1,63 @@
+// Copyright (C) 2017 Josh Wolfe. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Prefix increment for references to BigInt values
+esid: sec-prefix-increment-operator-runtime-semantics-evaluation
+info: |
+  1. Let expr be the result of evaluating UnaryExpression.
+  2. Let oldValue be ? ToNumeric(? GetValue(expr)).
+  3. Let newValue be ? Type(oldvalue)::add(oldValue, Type(oldValue)::unit).
+  4. Perform ? PutValue(expr, newValue).
+  5. Return newValue. 
+
+features: [BigInt]
+---*/
+
+var x = 0n;
+assert.sameValue(++x, 1n, "var x = 0n; ++x === 1n");
+assert.sameValue(x, 1n, "var x = 0n; ++x; x === 1n");
+
+var x = -1n;
+assert.sameValue(++x, 0n, "var x = -1n; ++x === 0n");
+assert.sameValue(x, 0n, "var x = -1n; ++x; x === 0n");
+
+var x = 123456n;
+assert.sameValue(++x, 123457n, "var x = 123456n; ++x === 123457n");
+assert.sameValue(x, 123457n, "var x = 123456n; ++x; x === 123457n");
+
+var x = -123457n;
+assert.sameValue(++x, -123456n, "var x = -123457n; ++x === -123456n");
+assert.sameValue(x, -123456n, "var x = -123457n; ++x; x === -123456n");
+
+var x = 0x1fffffffffffff00n;
+assert.sameValue(++x, 0x1fffffffffffff01n, "var x = 0x1fffffffffffff00n; ++x === 0x1fffffffffffff01n");
+assert.sameValue(x, 0x1fffffffffffff01n, "var x = 0x1fffffffffffff00n; ++x; x === 0x1fffffffffffff01n");
+
+var x = -0x1fffffffffffff01n;
+assert.sameValue(++x, -0x1fffffffffffff00n, "var x = -0x1fffffffffffff01n; ++x === -0x1fffffffffffff00n");
+assert.sameValue(x, -0x1fffffffffffff00n, "var x = -0x1fffffffffffff01n; ++x; x === -0x1fffffffffffff00n");
+
+var x = {y:0n};
+assert.sameValue(++x.y, 1n, "var x = {y:0n}; ++x.y === 1n");
+assert.sameValue(x.y, 1n, "var x = {y:0n}; ++x.y; x.y === 1n");
+
+var x = {y:{z:0n}};
+assert.sameValue(++x.y.z, 1n, "var x = {y:{z:0n}}; ++x.y.z === 1n");
+assert.sameValue(x.y.z, 1n, "var x = {y:{z:0n}}; ++x.y.z; x.y.z === 1n");
+
+var x = [0n];
+assert.sameValue(++x[0], 1n, "var x = [0n]; ++x[0] === 1n");
+assert.sameValue(x[0], 1n, "var x = [0n]; ++x[0]; x[0] === 1n");
+
+var x = [null, [null, null, 0n]];
+assert.sameValue(++x[1][2], 1n, "var x = [null, [null, null, 0n]]; ++x[1][2] === 1n");
+assert.sameValue(x[1][2], 1n, "var x = [null, [null, null, 0n]]; ++x[1][2]; x[1][2] === 1n");
+
+var x = {y:[0n]};
+assert.sameValue(++x.y[0], 1n, "var x = {y:[0n]}; ++x.y[0] === 1n");
+assert.sameValue(x.y[0], 1n, "var x = {y:[0n]}; ++x.y[0]; x.y[0] === 1n");
+
+var x = [{z:0n}];
+assert.sameValue(++x[0].z, 1n, "var x = [{z:0n}]; ++x[0].z === 1n");
+assert.sameValue(x[0].z, 1n, "var x = [{z:0n}]; ++x[0].z; x[0].z === 1n");