How to write an unit test in Jest to check for variable reassignment?
0
I am using Jest to test a helper function in my React application. Following is my test module:
import React from 'react';
import returnFirstTwoDrivers from '../../../src/Utils/returnFirstTwoDrivers';
describe('returnFirstTwoDrivers()', function () {
it('should be assigned to a constant', function ()
expect(function ()
returnFirstTwoDrivers = 'testing reassignment';
throw new TypeError();
).toThrow(TypeError);
);
Here, I am reassigning the returnFirstTwoDrivers variable and I am expecting this operation to throw an error because returnFirstTwoDrivers is a const variable.
When I run the test, the test suite fails to run and it is showing an error on line: returnFirstTwoDrivers = 'testing reassignment'; If anyone know how to fix this issue, please help me. Thank you.
javascript reactjs unit-testing jasmine jestjs
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
asked Nov 15 '18 at 15:36
socratessocrates
136110
|
show 2 more comments
0
I am using Jest to test a helper function in my React application. Following is my test module:
import React from 'react';
import returnFirstTwoDrivers from '../../../src/Utils/returnFirstTwoDrivers';
describe('returnFirstTwoDrivers()', function () {
it('should be assigned to a constant', function ()
expect(function ()
returnFirstTwoDrivers = 'testing reassignment';
throw new TypeError();
).toThrow(TypeError);
);
Here, I am reassigning the returnFirstTwoDrivers variable and I am expecting this operation to throw an error because returnFirstTwoDrivers is a const variable.
When I run the test, the test suite fails to run and it is showing an error on line: returnFirstTwoDrivers = 'testing reassignment'; If anyone know how to fix this issue, please help me. Thank you.
javascript reactjs unit-testing jasmine jestjs
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
asked Nov 15 '18 at 15:36
socratessocrates
136110
1
What are you actually trying to test here? This is a language-level error, not a runtime error.
– Dave Newton
Nov 15 '18 at 15:47
If i get you right then you basically check wether a const could be reassigned. But that is a language feature and you dont have to test it.
– Thomas Kleßen
Nov 15 '18 at 15:48
@DaveNewton I am trying to check whether I can reassignreturnFirstTwoDrivers
– socrates
Nov 15 '18 at 15:48
@socrates Obviously you cannot--but this is a compile-time error, not a runtime error. This makes no sense to test.
– Dave Newton
Nov 15 '18 at 15:49
yeah, I know. How do I check it? I do not wantreturnFirstTwoDriversto be assigned to aletorvar
– socrates
Nov 15 '18 at 15:49
|
show 2 more comments
0
0
0
1
I am using Jest to test a helper function in my React application. Following is my test module:
import React from 'react';
import returnFirstTwoDrivers from '../../../src/Utils/returnFirstTwoDrivers';
describe('returnFirstTwoDrivers()', function () {
it('should be assigned to a constant', function ()
expect(function ()
returnFirstTwoDrivers = 'testing reassignment';
throw new TypeError();
).toThrow(TypeError);
);
Here, I am reassigning the returnFirstTwoDrivers variable and I am expecting this operation to throw an error because returnFirstTwoDrivers is a const variable.
When I run the test, the test suite fails to run and it is showing an error on line: returnFirstTwoDrivers = 'testing reassignment'; If anyone know how to fix this issue, please help me. Thank you.
javascript reactjs unit-testing jasmine jestjs
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
asked Nov 15 '18 at 15:36
socratessocrates
136110
I am using Jest to test a helper function in my React application. Following is my test module:
import React from 'react';
import returnFirstTwoDrivers from '../../../src/Utils/returnFirstTwoDrivers';
describe('returnFirstTwoDrivers()', function () {
it('should be assigned to a constant', function ()
expect(function ()
returnFirstTwoDrivers = 'testing reassignment';
throw new TypeError();
).toThrow(TypeError);
);
Here, I am reassigning the returnFirstTwoDrivers variable and I am expecting this operation to throw an error because returnFirstTwoDrivers is a const variable.
When I run the test, the test suite fails to run and it is showing an error on line: returnFirstTwoDrivers = 'testing reassignment'; If anyone know how to fix this issue, please help me. Thank you.
javascript reactjs unit-testing jasmine jestjs
javascript reactjs unit-testing jasmine jestjs
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
asked Nov 15 '18 at 15:36
socratessocrates
136110
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
asked Nov 15 '18 at 15:36
socratessocrates
136110
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
edited Nov 15 '18 at 16:40
LazerBass
1,44531123
1,44531123
asked Nov 15 '18 at 15:36
socratessocrates
136110
asked Nov 15 '18 at 15:36
socratessocrates
136110
asked Nov 15 '18 at 15:36
socratessocrates
136110
136110
1
What are you actually trying to test here? This is a language-level error, not a runtime error.
– Dave Newton
Nov 15 '18 at 15:47
If i get you right then you basically check wether a const could be reassigned. But that is a language feature and you dont have to test it.
– Thomas Kleßen
Nov 15 '18 at 15:48
@DaveNewton I am trying to check whether I can reassignreturnFirstTwoDrivers
– socrates
Nov 15 '18 at 15:48
@socrates Obviously you cannot--but this is a compile-time error, not a runtime error. This makes no sense to test.
– Dave Newton
Nov 15 '18 at 15:49
yeah, I know. How do I check it? I do not wantreturnFirstTwoDriversto be assigned to aletorvar
– socrates
Nov 15 '18 at 15:49
|
show 2 more comments
1
What are you actually trying to test here? This is a language-level error, not a runtime error.
– Dave Newton
Nov 15 '18 at 15:47
If i get you right then you basically check wether a const could be reassigned. But that is a language feature and you dont have to test it.
– Thomas Kleßen
Nov 15 '18 at 15:48
@DaveNewton I am trying to check whether I can reassignreturnFirstTwoDrivers
– socrates
Nov 15 '18 at 15:48
@socrates Obviously you cannot--but this is a compile-time error, not a runtime error. This makes no sense to test.
– Dave Newton
Nov 15 '18 at 15:49
yeah, I know. How do I check it? I do not wantreturnFirstTwoDriversto be assigned to aletorvar
– socrates
Nov 15 '18 at 15:49
1
1
What are you actually trying to test here? This is a language-level error, not a runtime error.
– Dave Newton
Nov 15 '18 at 15:47
What are you actually trying to test here? This is a language-level error, not a runtime error.
– Dave Newton
Nov 15 '18 at 15:47
If i get you right then you basically check wether a const could be reassigned. But that is a language feature and you dont have to test it.
– Thomas Kleßen
Nov 15 '18 at 15:48
If i get you right then you basically check wether a const could be reassigned. But that is a language feature and you dont have to test it.
– Thomas Kleßen
Nov 15 '18 at 15:48
@DaveNewton I am trying to check whether I can reassign
returnFirstTwoDrivers– socrates
Nov 15 '18 at 15:48
@DaveNewton I am trying to check whether I can reassign
returnFirstTwoDrivers– socrates
Nov 15 '18 at 15:48
@socrates Obviously you cannot--but this is a compile-time error, not a runtime error. This makes no sense to test.
– Dave Newton
Nov 15 '18 at 15:49
@socrates Obviously you cannot--but this is a compile-time error, not a runtime error. This makes no sense to test.
– Dave Newton
Nov 15 '18 at 15:49
yeah, I know. How do I check it? I do not want
returnFirstTwoDrivers to be assigned to a let or var– socrates
Nov 15 '18 at 15:49
yeah, I know. How do I check it? I do not want
returnFirstTwoDrivers to be assigned to a let or var– socrates
Nov 15 '18 at 15:49
|
show 2 more comments
0
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1
What are you actually trying to test here? This is a language-level error, not a runtime error.
– Dave Newton
Nov 15 '18 at 15:47
If i get you right then you basically check wether a const could be reassigned. But that is a language feature and you dont have to test it.
– Thomas Kleßen
Nov 15 '18 at 15:48
@DaveNewton I am trying to check whether I can reassign
returnFirstTwoDrivers– socrates
Nov 15 '18 at 15:48
@socrates Obviously you cannot--but this is a compile-time error, not a runtime error. This makes no sense to test.
– Dave Newton
Nov 15 '18 at 15:49
yeah, I know. How do I check it? I do not want
returnFirstTwoDriversto be assigned to aletorvar– socrates
Nov 15 '18 at 15:49