ext/featurens: add empty filesmap tests for all

ext/featurens/aptsources/aptsources_test.go

@@ -37,6 +37,10 @@ BUG_REPORT_URL="https://bugs.debian.org/"`),
 				"etc/apt/sources.list": []byte(`deb http://httpredir.debian.org/debian unstable main`),
 			},
 		},
+		{
+			ExpectedNamespace: nil,
+			Files:             tarutil.FilesMap{},
+		},
 	}
 
 	featurens.TestDetector(t, &detector{}, testData)

ext/featurens/lsbrelease/lsbrelease_test.go

@@ -44,6 +44,10 @@ DISTRIB_CODENAME=wheezy
 DISTRIB_DESCRIPTION="Debian 7.1"`),
 			},
 		},
+		{
+			ExpectedNamespace: nil,
+			Files:             tarutil.FilesMap{},
+		},
 	}
 
 	featurens.TestDetector(t, &detector{}, testData)

ext/featurens/osrelease/osrelease_test.go

@@ -72,6 +72,10 @@ REDHAT_SUPPORT_PRODUCT="Fedora"
 REDHAT_SUPPORT_PRODUCT_VERSION=20`),
 			},
 		},
+		{
+			ExpectedNamespace: nil,
+			Files:             tarutil.FilesMap{},
+		},
 	}
 
 	featurens.TestDetector(t, &detector{}, testData)

ext/featurens/redhatrelease/redhatrelease_test.go

@@ -48,6 +48,10 @@ func TestDetector(t *testing.T) {
 				"etc/system-release": []byte(`CentOS Linux release 7.1.1503 (Core)`),
 			},
 		},
+		{
+			ExpectedNamespace: nil,
+			Files:             tarutil.FilesMap{},
+		},
 	}
 
 	featurens.TestDetector(t, &detector{}, testData)