diff --git a/format.js b/format.js
index 7c41960..00725dc 100644
--- a/format.js
+++ b/format.js
@@ -68,7 +68,7 @@ function toOffset(offsetMinutes) {
   const absoluteOffset = Math.abs(offsetMinutes);
   const hours = toTwoDigits(Math.floor(absoluteOffset / 60));
   const minutes = toTwoDigits(absoluteOffset % 60);
-  const sign = offsetMinutes >= 0 ? '-' : '+';
+  const sign = offsetMinutes > 0 ? '-' : '+';
 
   return `${sign}${hours}${minutes}`;
 }
diff --git a/test/format.spec.js b/test/format.spec.js
index 9c43d52..1d73b61 100644
--- a/test/format.spec.js
+++ b/test/format.spec.js
@@ -16,19 +16,19 @@ describe('toTwoDigits', () => {
     expect(toTwoDigits(value)).toBe(expected)
   })
 
-  test('throws TypeError if provided value is Infinity', () => {
+  it('throws TypeError if provided value is Infinity', () => {
     expect(() => toTwoDigits(Infinity)).toThrow(TypeError)
   })
 
-  test('throws TypeError if provided value is NaN', () => {
+  it('throws TypeError if provided value is NaN', () => {
     expect(() => toTwoDigits(NaN)).toThrow(TypeError)
   })
 
-  test('throws TypeError if provided value is a decimal number', () => {
+  it('throws TypeError if provided value is a decimal number', () => {
     expect(() => toTwoDigits(0.99)).toThrow(TypeError)
   })
 
-  test('throws TypeError if provided value is a string', () => {
+  it('throws TypeError if provided value is a string', () => {
     expect(() => toTwoDigits('0')).toThrow(TypeError)
   })
 })
@@ -42,19 +42,19 @@ describe('toOffset', () => {
     expect(toOffset(value)).toBe(expected)
   })
 
-  test('throws TypeError if provided value is Infinity', () => {
+  it('throws TypeError if provided value is Infinity', () => {
     expect(() => toOffset(Infinity)).toThrow(TypeError)
   })
 
-  test('throws TypeError if provided value is NaN', () => {
+  it('throws TypeError if provided value is NaN', () => {
     expect(() => toOffset(NaN)).toThrow(TypeError)
   })
 
-  test('throws TypeError if provided value is a decimal number', () => {
+  it('throws TypeError if provided value is a decimal number', () => {
     expect(() => toOffset(60.5)).toThrow(TypeError)
   })
 
-  test('throws TypeError if provided value is a string', () => {
+  it('throws TypeError if provided value is a string', () => {
     expect(() => toOffset('60')).toThrow(TypeError)
   })
 })
@@ -77,19 +77,19 @@ describe('toShortMonth', () => {
     expect(toShortMonth(value)).toBe(expected)
   })
 
-  test('throws TypeError for a non-valid month number', () => {
+  it('throws TypeError for a non-valid month number', () => {
     expect(() => toShortMonth(13)).toThrow(TypeError)
   })
 })
 
 describe('toCommonAccessLogDateFormat', () => {
-  test('correctly formats a date', () => {
+  it('correctly formats a date', () => {
     const date = new Date('2020-01-01T12:34:56Z')
     const expectedValue = '01/Jan/2020:10:34:56 +0200'
     expect(toCommonAccessLogDateFormat(date)).toBe(expectedValue)
   })
 
-  test('throws TypeError for non-Date value', () => {
+  it('throws TypeError for non-Date value', () => {
     expect(() => toCommonAccessLogDateFormat({})).toThrow(TypeError)
   })
 })
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