diff --git a/test/language/expressions/logical-assignment/lgcl-and-arguments-strict.js b/test/language/expressions/logical-assignment/lgcl-and-arguments-strict.js
new file mode 100644
index 00000000000..c23e4a88f92
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-and-arguments-strict.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators
+description: >
+    Strict Mode - SyntaxError is thrown if the identifier arguments
+    appear as the LeftHandSideExpression of a Logical Assignment
+    operator(&&=)
+flags: [onlyStrict]
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+arguments &&= 20;
diff --git a/test/language/expressions/logical-assignment/lgcl-and-eval-strict.js b/test/language/expressions/logical-assignment/lgcl-and-eval-strict.js
new file mode 100644
index 00000000000..345ea960e1a
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-and-eval-strict.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators
+description: >
+    Strict Mode - SyntaxError is thrown if the identifier eval appear
+    as the LeftHandSideExpression of a Logical Assignment operator(&&=)
+flags: [onlyStrict]
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+eval &&= 20;
diff --git a/test/language/expressions/logical-assignment/lgcl-and-non-simple.js b/test/language/expressions/logical-assignment/lgcl-and-non-simple.js
new file mode 100644
index 00000000000..977ace323ac
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-and-non-simple.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+info: |
+    It is an early Syntax Error if AssignmentTargetType of
+    LeftHandSideExpression is invalid or strict.
+description: Logical "&&=" assignment with non-simple target
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+1 &&= 1;
diff --git a/test/language/expressions/logical-assignment/lgcl-and-whitespace.js b/test/language/expressions/logical-assignment/lgcl-and-whitespace.js
new file mode 100644
index 00000000000..35b81571356
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-and-whitespace.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+info: |
+    White Space and Line Terminator between LeftHandSideExpression and "@="
+    or between "@=" and AssignmentExpression are allowed
+esid: sec-assignment-operators
+description: Checking by evaluating expression "x[...]&&=[...]y"
+features: [logical-assignment-operators]
+---*/
+var x;
+
+x = 1;
+assert.sameValue(x	&&=	2, 2, 'U+0009 (expression)');
+assert.sameValue(x, 2, 'U+0009 (side effect)');
+
+x = 1;
+assert.sameValue(x&&=2, 2, 'U+000B (expression)');
+assert.sameValue(x, 2, 'U+000B (side effect)');
+
+x = 1;
+assert.sameValue(x&&=2, 2, 'U+000C (expression)');
+assert.sameValue(x, 2, 'U+000C (side effect)');
+
+x = 1;
+assert.sameValue(x &&= 2, 2, 'U+0020 (expression)');
+assert.sameValue(x, 2, 'U+0020 (side effect)');
+
+x = 1;
+assert.sameValue(x &&= 2, 2, 'U+00A0 (expression)');
+assert.sameValue(x, 2, 'U+00A0 (side effect)');
+
+x = 1;
+assert.sameValue(x
+&&=
+2, 2, 'U+000A (expression)');
+assert.sameValue(x, 2, 'U+000A (side effect)');
+
+x = 1;
+assert.sameValue(x
+&&=
+2, 2, 'U+000D (expression)');
+assert.sameValue(x, 2, 'U+000D (side effect)');
+
+x = 1;
+assert.sameValue(x
&&=
2, 2, 'U+2028 (expression)');
+assert.sameValue(x, 2, 'U+2028 (side effect)');
+
+x = 1;
+assert.sameValue(x
&&=
2, 2, 'U+2029 (expression)');
+assert.sameValue(x, 2, 'U+2029 (side effect)');
+
+x = 1;
+assert.sameValue(x	  
+

&&=	  
+

2, 2, 'U+0009U+000BU+000CU+0020U+00A0U+000AU+000DU+2028U+2029 (expression)');
+assert.sameValue(x, 2, 'U+0009U+000BU+000CU+0020U+00A0U+000AU+000DU+2028U+2029 (side effect)');
diff --git a/test/language/expressions/logical-assignment/lgcl-nullish-arguments-strict.js b/test/language/expressions/logical-assignment/lgcl-nullish-arguments-strict.js
new file mode 100644
index 00000000000..499f9ea045e
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-nullish-arguments-strict.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators
+description: >
+    Strict Mode - SyntaxError is thrown if the identifier arguments
+    appear as the LeftHandSideExpression of a Logical Assignment
+    operator(??=)
+flags: [onlyStrict]
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+arguments ??= 20;
diff --git a/test/language/expressions/logical-assignment/lgcl-nullish-eval-strict.js b/test/language/expressions/logical-assignment/lgcl-nullish-eval-strict.js
new file mode 100644
index 00000000000..70cd3c9bca5
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-nullish-eval-strict.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators
+description: >
+    Strict Mode - SyntaxError is thrown if the identifier eval appear
+    as the LeftHandSideExpression of a Logical Assignment operator(??=)
+flags: [onlyStrict]
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+eval ??= 20;
diff --git a/test/language/expressions/logical-assignment/lgcl-nullish-non-simple.js b/test/language/expressions/logical-assignment/lgcl-nullish-non-simple.js
new file mode 100644
index 00000000000..fe312171665
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-nullish-non-simple.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+info: |
+    It is an early Syntax Error if AssignmentTargetType of
+    LeftHandSideExpression is invalid or strict.
+description: Logical "??=" assignment with non-simple target
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+1 ??= 1;
diff --git a/test/language/expressions/logical-assignment/lgcl-nullish-whitespace.js b/test/language/expressions/logical-assignment/lgcl-nullish-whitespace.js
new file mode 100644
index 00000000000..7fc6484207d
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-nullish-whitespace.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+info: |
+    White Space and Line Terminator between LeftHandSideExpression and "@="
+    or between "@=" and AssignmentExpression are allowed
+esid: sec-assignment-operators
+description: Checking by evaluating expression "x[...]??=[...]y"
+features: [logical-assignment-operators]
+---*/
+var x;
+
+x = null;
+assert.sameValue(x	??=	1, 1, 'U+0009 (expression)');
+assert.sameValue(x, 1, 'U+0009 (side effect)');
+
+x = null;
+assert.sameValue(x??=1, 1, 'U+000B (expression)');
+assert.sameValue(x, 1, 'U+000B (side effect)');
+
+x = null;
+assert.sameValue(x??=1, 1, 'U+000C (expression)');
+assert.sameValue(x, 1, 'U+000C (side effect)');
+
+x = null;
+assert.sameValue(x ??= 1, 1, 'U+0020 (expression)');
+assert.sameValue(x, 1, 'U+0020 (side effect)');
+
+x = null;
+assert.sameValue(x ??= 1, 1, 'U+00A0 (expression)');
+assert.sameValue(x, 1, 'U+00A0 (side effect)');
+
+x = null;
+assert.sameValue(x
+??=
+1, 1, 'U+000A (expression)');
+assert.sameValue(x, 1, 'U+000A (side effect)');
+
+x = null;
+assert.sameValue(x
+??=
+1, 1, 'U+000D (expression)');
+assert.sameValue(x, 1, 'U+000D (side effect)');
+
+x = null;
+assert.sameValue(x
??=
1, 1, 'U+2028 (expression)');
+assert.sameValue(x, 1, 'U+2028 (side effect)');
+
+x = null;
+assert.sameValue(x
??=
1, 1, 'U+2029 (expression)');
+assert.sameValue(x, 1, 'U+2029 (side effect)');
+
+x = null;
+assert.sameValue(x	  
+

??=	  
+

1, 1, 'U+0009U+000BU+000CU+0020U+00A0U+000AU+000DU+2028U+2029 (expression)');
+assert.sameValue(x, 1, 'U+0009U+000BU+000CU+0020U+00A0U+000AU+000DU+2028U+2029 (side effect)');
diff --git a/test/language/expressions/logical-assignment/lgcl-or-arguments-strict.js b/test/language/expressions/logical-assignment/lgcl-or-arguments-strict.js
new file mode 100644
index 00000000000..c67b5355016
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-or-arguments-strict.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators
+description: >
+    Strict Mode - SyntaxError is thrown if the identifier arguments
+    appear as the LeftHandSideExpression of a Logical Assignment
+    operator(||=)
+flags: [onlyStrict]
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+arguments ||= 20;
diff --git a/test/language/expressions/logical-assignment/lgcl-or-eval-strict.js b/test/language/expressions/logical-assignment/lgcl-or-eval-strict.js
new file mode 100644
index 00000000000..1d3a9e23472
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-or-eval-strict.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators
+description: >
+    Strict Mode - SyntaxError is thrown if the identifier eval appear
+    as the LeftHandSideExpression of a Logical Assignment operator(||=)
+flags: [onlyStrict]
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+eval ||= 20;
diff --git a/test/language/expressions/logical-assignment/lgcl-or-non-simple.js b/test/language/expressions/logical-assignment/lgcl-or-non-simple.js
new file mode 100644
index 00000000000..90639520ec6
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-or-non-simple.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+info: |
+    It is an early Syntax Error if AssignmentTargetType of
+    LeftHandSideExpression is invalid or strict.
+description: Logical "||=" assignment with non-simple target
+negative:
+  phase: parse
+  type: SyntaxError
+features: [logical-assignment-operators]
+---*/
+$DONOTEVALUATE();
+
+1 ||= 1;
diff --git a/test/language/expressions/logical-assignment/lgcl-or-whitespace.js b/test/language/expressions/logical-assignment/lgcl-or-whitespace.js
new file mode 100644
index 00000000000..bae1526633d
--- /dev/null
+++ b/test/language/expressions/logical-assignment/lgcl-or-whitespace.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+info: |
+    White Space and Line Terminator between LeftHandSideExpression and "@="
+    or between "@=" and AssignmentExpression are allowed
+esid: sec-assignment-operators
+description: Checking by evaluating expression "x[...]||=[...]y"
+features: [logical-assignment-operators]
+---*/
+var x;
+
+x = 0;
+assert.sameValue(x	||=	1, 1, 'U+0009 (expression)');
+assert.sameValue(x, 1, 'U+0009 (side effect)');
+
+x = 0;
+assert.sameValue(x||=1, 1, 'U+000B (expression)');
+assert.sameValue(x, 1, 'U+000B (side effect)');
+
+x = 0;
+assert.sameValue(x||=1, 1, 'U+000C (expression)');
+assert.sameValue(x, 1, 'U+000C (side effect)');
+
+x = 0;
+assert.sameValue(x ||= 1, 1, 'U+0020 (expression)');
+assert.sameValue(x, 1, 'U+0020 (side effect)');
+
+x = 0;
+assert.sameValue(x ||= 1, 1, 'U+00A0 (expression)');
+assert.sameValue(x, 1, 'U+00A0 (side effect)');
+
+x = 0;
+assert.sameValue(x
+||=
+1, 1, 'U+000A (expression)');
+assert.sameValue(x, 1, 'U+000A (side effect)');
+
+x = 0;
+assert.sameValue(x
+||=
+1, 1, 'U+000D (expression)');
+assert.sameValue(x, 1, 'U+000D (side effect)');
+
+x = 0;
+assert.sameValue(x
||=
1, 1, 'U+2028 (expression)');
+assert.sameValue(x, 1, 'U+2028 (side effect)');
+
+x = 0;
+assert.sameValue(x
||=
1, 1, 'U+2029 (expression)');
+assert.sameValue(x, 1, 'U+2029 (side effect)');
+
+x = 0;
+assert.sameValue(x	  
+

||=	  
+

1, 1, 'U+0009U+000BU+000CU+0020U+00A0U+000AU+000DU+2028U+2029 (expression)');
+assert.sameValue(x, 1, 'U+0009U+000BU+000CU+0020U+00A0U+000AU+000DU+2028U+2029 (side effect)');