You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: matrix_test.go
    path of file: ./repos/pixel
    
    the code of the file until where you have to start completion: package pixel_test

import (
	"fmt"
	"math
    
func TestMatrix_Unproject(t *testing.T) {
	const delta = 1e-15
	t.Run("for rotated matrix", func(t *testing.T) {
		matrix := pixel.IM.
			Rotated(pixel.ZV, math.Pi/2)
		unprojected := matrix.Unproject(pixel.V(0, 1))
		assert.InDelta(t, unprojected.X, 1, delta)
		assert.InDelta(t, unprojected.Y, 0, delta)
	})
	t.Run("for moved matrix", func(t *testing.T) {
		matrix := pixel.IM.
			Moved(pixel.V(1, 2))
		unprojected := matrix.Unproject(pixel.V(2, 5))
		assert.InDelta(t, unprojected.X, 1, delta)
		assert.InDelta(t, unprojected.Y, 3, delta)
	})
	t.Run("for scaled matrix", func(t *testing.T) {
		matrix := pixel.IM.
			Scaled(pixel.ZV, 2)
		unprojected := matrix.Unproject(pixel.V(2, 4))
		assert.InDelta(t, unprojected.X, 1, delta)
		assert.InDelta(t, unprojected.Y, 2, delta)
	})
	t.Run("for scaled, rotated and moved matrix", func(t *testing.T) {
		matrix := pixel.IM.
			Scaled(pixel.ZV, 2).
			Rotated(pixel.ZV, math.Pi/2).
			Moved(pixel.V(2, 2))
		unprojected := matrix.Unproject(pixel.V(-2, 6))
		assert.InDelta(t, unprojected.X, 2, delta)
		assert.InDelta(t, unprojected.Y, 2, delta)
	})
	t.Run("for rotated and moved matrix", func(t *testing.T) {
		matrix := pixel.IM.
			Rotated(pixel.ZV, math.Pi/2).
			Moved(pixel.V(1, 1))
		unprojected := matrix.Unproject(pixel.V(1, 2))
		assert.InDelta(t, unprojected.X, 1, delta)
		assert.InDelta(t, unprojected.Y, 0, delta)
	})
	t.Run("for projected vertices using all kinds of matrices", func(t *testing.T) {
		namedMatrices := map[string]pixel.Matrix{
			"IM":                        pixel.IM,
			"Scaled":                    pixel.IM.Scaled(pixel.ZV, 0.5),
			"Scaled x 2":                pixel.IM.Scaled(pixel.ZV, 2),
			"Rotated":                   pixel.IM.Rotated(pixel.ZV, math.Pi/4),
			"Moved":                     pixel.IM.Moved(pixel.V(0.5, 1)),
			"Moved 2":                   pixel.IM.Moved(pixel.V(-1, -0.5)),
			"Scaled and Rotated":        pixel.IM.Scaled(pixel.ZV, 0.5).Rotated(pixel.ZV, math.Pi/4),
			"Scaled, Rotated and Moved": pixel.IM.Scaled(pixel.ZV, 0.5).Rotated(pixel.ZV, math.Pi/4).Moved(pixel.V(1, 2)),
			"Rotated and Moved":         pixel.IM.Rotated(pixel.ZV, math.Pi/4).Moved(pixel.V(1, 2)),
		}
		vertices := [...]pixel.Vec{
			pixel.V(0, 0),
			pixel.V(5, 0),
			pixel.V(5, 10),
			pixel.V(0, 10),
			pixel.V(-5, 10),
			pixel.V(-5, 0),
			pixel.V(-5, -10),
			pixel.V(0, -10),
			pixel.V(5, -10),
		}
		for matrixName, matrix := range namedMatrices {
			for _, vertex := range vertices {
				testCase := fmt.Sprintf("for matrix %s and vertex %v", matrixName, vertex)
				t.Run(testCase, func(t *testing.T) {
					projected := matrix.Project(vertex)
					unprojected := matrix.Unproject(projected)
					assert.InDelta(t, vertex.X, unprojected.X, delta)
					assert.InDelta(t, vertex.Y, unprojected.Y, delta)
				})
			}
		}
	})
	t.Run("for singular matrix", func(t *testing.T) {
		matrix := pixel.Matrix{0, 0, 0, 0, 0, 0}
		unprojected := matrix.Unproject(pixel.ZV)
		assert.True(t, math.IsNaN(unprojected.X))
		assert.True(t, math.IsNaN(unprojected.Y))
	})
}