disk,osbuild: use t.Name() in test update instruction message

Use t.Name() in the tests that use the TestPartitionTables and expect
all cases to be covered so that we don't need to keep the message in
sync with the function name.

The message for TestForEachFSTabEntity() was wrong.

pkg/disk/disk_test.go

@@ -987,22 +987,23 @@ func TestForEachFSTabEntity(t *testing.T) {
 	}
 
 	for name := range testdisk.TestPartitionTables {
-		t.Run(name, func(t *testing.T) {
-
+		// use a different name for the internal testing argument so we can
+		// refer to the global test by t.Name() in the error message
+		t.Run(name, func(ts *testing.T) {
 			var targets []string
 			targetCollectorCB := func(ent disk.FSTabEntity, _ []disk.Entity) error {
 				targets = append(targets, ent.GetFSFile())
 				return nil
 			}
 
-			require := require.New(t)
+			require := require.New(ts)
 			pt := testdisk.TestPartitionTables[name]
 
 			// print an informative failure message if a new test partition
 			// table is added and this test is not updated (instead of failing
 			// at the final Equal() check)
 			exp, ok := expectedEntityPaths[name]
-			require.True(ok, "expected options not defined for test partition table %q: please update the TestNewFSTabStageOptions test", name)
+			require.True(ok, "expected test result not defined for test partition table %q: please update the %s test", name, t.Name())
 
 			err := pt.ForEachFSTabEntity(targetCollectorCB)
 			// the callback never returns an error, but let's check it anyway

pkg/osbuild/fstab_stage_test.go

@@ -104,8 +104,10 @@ func TestNewFSTabStageOptions(t *testing.T) {
 	}
 	// Use the test partition tables from the disk package.
 	for name := range testdisk.TestPartitionTables {
-		t.Run(name, func(t *testing.T) {
-			require := require.New(t)
+		// use a different name for the internal testing argument so we can
+		// refer to the global test by t.Name() in the error message
+		t.Run(name, func(ts *testing.T) {
+			require := require.New(ts)
 			pt := testdisk.TestPartitionTables[name]
 
 			// math/rand is good enough in this case
@@ -118,7 +120,7 @@ func TestNewFSTabStageOptions(t *testing.T) {
 			// table is added and this test is not updated (instead of failing
 			// at the final Equal() check)
 			exp, ok := expectedOptions[name]
-			require.True(ok, "expected options not defined for test partition table %q: please update the TestNewFSTabStageOptions test", name)
+			require.True(ok, "expected test result not defined for test partition table %q: please update the %s test", name, t.Name())
 
 			options, err := NewFSTabStageOptions(&pt)
 			require.NoError(err)