Common Matchers in Jest

// Equality
expect(2 + 2).toBe(4)              // Exact equality ===
expect({name: 'jest'}).toEqual({name: 'jest'}) // Deep equality

// Truthiness
expect(value).toBeTruthy()
expect(value).toBeFalsy()
expect(value).toBeNull()
expect(value).toBeUndefined()
expect(value).toBeDefined()

// Numbers
expect(2 + 2).toBeGreaterThan(3)
expect(2 + 2).toBeGreaterThanOrEqual(4)
expect(2 + 2).toBeLessThan(5)
expect(0.1 + 0.2).toBeCloseTo(0.3) // For floating point

// Strings
expect('team').toMatch(/I/)
expect('Christoph').toMatch('stop')

// Arrays and Iterables
expect(['Alice', 'Bob']).toContain('Alice')
expect(new Set(['Alice', 'Bob'])).toContain('Alice')
expect(['Alice', 'Bob']).toHaveLength(2)