refactor: add internal/assert.go and rewrite all unit funcs string_test.go with assert

internal/assert_test.go

@@ -0,0 +1,28 @@
+package internal
+
+import (
+	"testing"
+)
+
+func TestAssert(t *testing.T) {
+	assert := NewAssert(t, "TestAssert")
+	assert.Equal(0, 0)
+	assert.NotEqual(1, 0)
+	assert.Greater(1, 0)
+	assert.Less(0, 1)
+
+	assert.Greater(1.1, 0.1)
+	assert.Less(0.1, 1.1)
+
+	assert.Equal("abc", "abc")
+	assert.NotEqual("abc", "abd")
+	assert.Less("abc", "abd")
+	assert.Greater("abd", "abc")
+
+	assert.Equal([]int{1, 2, 3}, []int{1, 2, 3})
+	assert.NotEqual([]int{1, 2, 3}, []int{1, 2})
+
+	assert.IsNil(nil)
+	assert.IsNotNil("abc")
+
+}