Raise error if malformed test metadata is given

tests/test/script/data/.fmf/version

@@ -0,0 +1 @@
+1

tests/test/script/data/tests/foo.fmf

@@ -0,0 +1,9 @@
+/pos:
+    summary: Normal test metadata should be accepted
+    test: 'false'
+    framework: shell
+
+/neg:
+    summary: Malformed test metadata should be rejected
+    test: false
+    framework: shell

tests/test/script/main.fmf

@@ -0,0 +1 @@
+summary: Verify test metadata should be string

tests/test/script/test.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+. /usr/share/beakerlib/beakerlib.sh || exit 1
+
+rlJournalStart
+    rlPhaseStartSetup
+        rlRun "pushd data"
+        rlRun "set -o pipefail"
+    rlPhaseEnd
+
+    rlPhaseStartTest "Normal test metadata"
+        rlRun -s "tmt tests ls /pos" 0
+        rlAssertGrep "/tests/foo/pos" $rlRun_LOG
+    rlPhaseEnd
+
+    rlPhaseStartTest "Malformed test metadata"
+        rlRun -s "tmt tests ls /neg" "1-255"
+        rlAssertGrep "Field '/tests/foo/neg:test' must be a string, 'bool' found" $rlRun_LOG
+    rlPhaseEnd
+
+    rlPhaseStartCleanup
+        rlRun "popd"
+    rlPhaseEnd
+rlJournalEnd

tmt/base.py

@@ -38,7 +38,8 @@
 from tmt.lint import LinterOutcome, LinterReturn
 from tmt.result import Result, ResultOutcome
 from tmt.utils import (Command, EnvironmentType, FmfContextType, Path,
-                       ShellScript, WorkdirArgumentType, field, verdict)
+                       ShellScript, WorkdirArgumentType, field,
+                       normalize_shell_script, verdict)
 
 if sys.version_info >= (3, 8):
     from typing import Literal, TypedDict
@@ -911,8 +912,7 @@ class Test(
     # `test` is mandatory, must exist, so how to initialize if it's missing :(
     test: Optional[ShellScript] = field(
         default=None,
-        normalize=lambda key_address, raw_value, logger:
-            None if raw_value is None else ShellScript(raw_value))
+        normalize=normalize_shell_script)
     path: Optional[Path] = field(
         default=None,
         normalize=lambda key_address, raw_value, logger:

tmt/utils.py

@@ -4391,6 +4391,25 @@ def normalize_shell_script_list(
     raise NormalizationError(key_address, value, 'a string or a list of strings')
 
 
+def normalize_shell_script(
+        key_address: str,
+        value: Union[None, str],
+        logger: tmt.log.Logger) -> Optional[ShellScript]:
+    """
+    Normalize a single shell script input that may be unset.
+
+    :param value: input value from key source.
+    """
+
+    if value is None:
+        return None
+
+    if isinstance(value, str):
+        return ShellScript(value)
+
+    raise NormalizationError(key_address, value, 'a string')
+
+
 def normalize_fmf_context(
         key_address: str,
         value: Optional[Dict[Any, Any]],