unit test to reproduce issue #691

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/distro/identify_test.go

@@ -25,6 +25,11 @@ func TestIdentifyDistro(t *testing.T) {
 			Type:    Alpine,
 			Version: "3.11.6",
 		},
+		{
+			fixture: "test-fixtures/os/alpine-edge",
+			Type:    Alpine,
+			Version: "3.15.0_alpha20210804",
+		},
 		{
 			fixture: "test-fixtures/os/amazon",
 			Type:    AmazonLinux,

syft/distro/test-fixtures/os/alpine-edge/etc/os-release

@@ -0,0 +1,6 @@
+NAME="Alpine Linux"
+ID=alpine
+VERSION_ID=3.15.0_alpha20210804
+PRETTY_NAME="Alpine Linux edge"
+HOME_URL="https://alpinelinux.org/"
+BUG_REPORT_URL="https://bugs.alpinelinux.org/"