Re-wrote a bunch to try to figure out why things weren't working.

Turned out I was reading if a block was compressed exactly opposite.
Started to work more on looking up dirs.

squash_test.go

@@ -0,0 +1,104 @@
+package squashfs
+
+import (
+	"io"
+	"net/http"
+	"os"
+	"testing"
+
+	goappimage "github.com/CalebQ42/GoAppImage"
+)
+
+const (
+	downloadURL  = "https://github.com/zilti/code-oss.AppImage/releases/download/continuous/Code_OSS-x86_64.AppImage"
+	appImageName = "Code_OSS.AppImage"
+	squashfsName = "Code_OSS.Squashfs"
+)
+
+func TestMain(t *testing.T) {
+	t.Parallel()
+	wd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	squashFil, err := os.Open(wd + "/testing/" + squashfsName)
+	if os.IsNotExist(err) {
+		TestCreateSquashFromAppImage(t)
+		squashFil, err = os.Open(wd + "/testing/" + squashfsName)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	defer squashFil.Close()
+	stat, _ := squashFil.Stat()
+	rdr, err := NewSquashfsReader(io.NewSectionReader(squashFil, 0, stat.Size()))
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = rdr.readRootDirTable()
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Fatal(err)
+}
+
+func TestCreateSquashFromAppImage(t *testing.T) {
+	wd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = os.Mkdir(wd+"/testing", 0777)
+	if err != nil && !os.IsExist(err) {
+		t.Fatal(err)
+	}
+	_, err = os.Open(wd + "/testing/" + appImageName)
+	if os.IsNotExist(err) {
+		downloadTestAppImage(t, wd+"/testing")
+		_, err = os.Open(wd + "/testing/" + appImageName)
+		if err != nil {
+			t.Fatal(err)
+		}
+	} else if err != nil {
+		t.Fatal(err)
+	}
+	ai := goappimage.NewAppImage(wd + "/testing/" + appImageName)
+	aiFil, err := os.Open(wd + "/testing/" + appImageName)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer aiFil.Close()
+	aiFil.Seek(ai.Offset, 0)
+	os.Remove(wd + "/testing/" + squashfsName)
+	aiSquash, err := os.Create(wd + "/testing/" + squashfsName)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = io.Copy(aiSquash, aiFil)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func downloadTestAppImage(t *testing.T, dir string) {
+	//seems to time out. Need to fix that at some point
+	appImage, err := os.Create(dir + "/" + appImageName)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer appImage.Close()
+	check := http.Client{
+		CheckRedirect: func(r *http.Request, via []*http.Request) error {
+			r.URL.Opaque = r.URL.Path
+			return nil
+		},
+	}
+	resp, err := check.Get(downloadURL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	_, err = io.Copy(appImage, resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+}