[v2,5/6] oeqa/utils/commands: use the tinfoil helper in get_bb_var

diff --git a/meta/lib/oeqa/utils/commands.py b/meta/lib/oeqa/utils/commands.py
index f4876ca6c9..10422fea24 100644
--- a/meta/lib/oeqa/utils/commands.py
+++ b/meta/lib/oeqa/utils/commands.py
@@ -253,12 +253,13 @@  def get_bb_env(target=None, postconfig=None):
     else:
         return bitbake("-e", postconfig=postconfig).output
 
-def get_bb_vars(variables=None, target=None, postconfig=None):
-    """Get values of multiple bitbake variables or variable flags
+def _get_bb_values(variables=None, target=None, postconfig=None):
+    """Read bitbake variables or variable flags with a single tinfoil session
 
-    All values are read with a single tinfoil session. Variable flags can be
-    requested with the VAR[flag] syntax. If variables is None, all variables
-    are returned. Unset or empty values are returned as None.
+    Variable flags can be requested with the VAR[flag] syntax. If variables
+    is None, all variables are returned. Values which are not strings are
+    converted with str() as bitbake -e does, unset variables or flags are
+    returned as None.
     """
     import bb.tinfoil
 
@@ -279,7 +280,7 @@  def get_bb_vars(variables=None, target=None, postconfig=None):
                 if var.startswith('__') or d.getVarFlag(var, 'func'):
                     continue
                 val = d.getVar(var)
-                if val is not None and val != '':
+                if val is not None:
                     values[var] = str(val)
             return values
 
@@ -290,24 +291,29 @@  def get_bb_vars(variables=None, target=None, postconfig=None):
                 val = d.getVarFlag(match.group('var'), match.group('flag'))
             else:
                 val = d.getVar(var)
-            values[var] = str(val) if val is not None and val != '' else None
+            values[var] = str(val) if val is not None else None
     return values
 
+def get_bb_vars(variables=None, target=None, postconfig=None):
+    """Get values of multiple bitbake variables or variable flags
+
+    All values are read with a single tinfoil session. Variable flags can be
+    requested with the VAR[flag] syntax. If variables is None, all variables
+    are returned. Unset or empty values are returned as None.
+    """
+    values = _get_bb_values(variables, target, postconfig)
+    if variables is None:
+        return {var: val for var, val in values.items() if val}
+    return {var: val or None for var, val in values.items()}
+
 def get_bb_var(var, target=None, postconfig=None):
-    if postconfig:
-        return bitbake("-e %s" % target or "", postconfig=postconfig).output
-    else:
-        # Fast-path for the non-postconfig case
-        cmd = ["bitbake-getvar", "--quiet", "--value", var]
-        if target:
-            cmd.extend(["--recipe", target])
-        try:
-            return subprocess.run(cmd, check=True, text=True, stdout=subprocess.PIPE).stdout.strip()
-        except subprocess.CalledProcessError as e:
-            # We need to return None not the empty string if the variable hasn't been set.
-            if e.returncode == 1:
-                return None
-            raise
+    """Get the value of a bitbake variable or variable flag
+
+    A variable flag can be requested with the VAR[flag] syntax. Unset values
+    are returned as None, empty values as an empty string.
+    """
+    val = _get_bb_values([var], target, postconfig)[var]
+    return val.strip() if val is not None else None
 
 def get_test_layer(bblayers=None):
     if bblayers is None: