feat: report unknowns in sbom (#2998)

Signed-off-by: Keith Zantow <kzantow@gmail.com>
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Co-authored-by: Alex Goodman <wagoodman@users.noreply.github.com>

test/cli/unknowns_test.go

@@ -0,0 +1,39 @@
+package cli
+
+import (
+	"testing"
+)
+
+func Test_Unknowns(t *testing.T) {
+	unknownsImage := getFixtureImage(t, "image-unknowns")
+
+	tests := []struct {
+		name       string
+		args       []string
+		env        map[string]string
+		assertions []traitAssertion
+	}{
+		{
+			name: "unknown executables",
+			args: []string{"scan", "-o", "json", unknownsImage, "--from", "docker-archive"},
+			env:  map[string]string{"SYFT_FORMAT_PRETTY": "true"},
+			assertions: []traitAssertion{
+				assertJsonReport,
+				assertInOutput(`no package identified in executable file`),
+				assertInOutput(`unable to read files from java archive`),
+				assertInOutput(`no package identified in archive`),
+				assertSuccessfulReturnCode,
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			cmd, stdout, stderr := runSyft(t, test.env, test.args...)
+			for _, traitFn := range test.assertions {
+				traitFn(t, stdout, stderr, cmd.ProcessState.ExitCode())
+			}
+			logOutputOnFailure(t, cmd, stdout, stderr)
+		})
+	}
+}