tests/qtest: Introduce qtest_has_machine_with_env

Add a variant of qtest_has_machine() that receives an environment
variable containing an alternate QEMU binary path.

Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231018192741.25885-5-farosas@suse.de>

tests/qtest/libqtest.c

@@ -1565,12 +1565,12 @@ void qtest_cb_for_every_machine(void (*cb)(const char *machine),
     }
 }
 
-bool qtest_has_machine(const char *machine)
+bool qtest_has_machine_with_env(const char *var, const char *machine)
 {
     struct MachInfo *machines;
     int i;
 
-    machines = qtest_get_machines(NULL);
+    machines = qtest_get_machines(var);
 
     for (i = 0; machines[i].name != NULL; i++) {
         if (g_str_equal(machine, machines[i].name) ||
@@ -1582,6 +1582,11 @@ bool qtest_has_machine(const char *machine)
     return false;
 }
 
+bool qtest_has_machine(const char *machine)
+{
+    return qtest_has_machine_with_env(NULL, machine);
+}
+
 bool qtest_has_device(const char *device)
 {
     static QList *list;

tests/qtest/libqtest.h

@@ -930,6 +930,15 @@ void qtest_cb_for_every_machine(void (*cb)(const char *machine),
  */
 bool qtest_has_machine(const char *machine);
 
+/**
+ * qtest_has_machine_with_env:
+ * @var: Environment variable from where to take the QEMU binary
+ * @machine: The machine to look for
+ *
+ * Returns: true if the machine is available in the specified binary.
+ */
+bool qtest_has_machine_with_env(const char *var, const char *machine);
+
 /**
  * qtest_has_device:
  * @device: The device to look for