diff --git a/src/modules/flow/test/boolean-generator.c b/src/modules/flow/test/boolean-generator.c
index 1f3326558..79c1679e4 100644
--- a/src/modules/flow/test/boolean-generator.c
+++ b/src/modules/flow/test/boolean-generator.c
@@ -78,7 +78,7 @@ boolean_generator_open(
 
     if (opts->sequence == NULL || *opts->sequence == '\0') {
         SOL_ERR("Option 'sequence' is either NULL or empty.");
-        return -1;
+        return -EINVAL;
     }
 
     mdata->it = mdata->sequence = strdup(opts->sequence);
diff --git a/src/modules/flow/test/float-generator.c b/src/modules/flow/test/float-generator.c
index fde044461..6faf78cd3 100644
--- a/src/modules/flow/test/float-generator.c
+++ b/src/modules/flow/test/float-generator.c
@@ -95,7 +95,7 @@ float_generator_open(
         }
         if (it == tail) {
             SOL_WRN("Failed to convert option 'sequence' to int %s", it);
-            errno = -EINVAL;
+            errno = EINVAL;
             goto error;
         }
         it = tail;
@@ -107,10 +107,10 @@ float_generator_open(
     return 0;
 
 no_memory:
-    errno = -ENOMEM;
+    errno = ENOMEM;
 error:
     sol_vector_clear(&mdata->values);
-    return errno;
+    return -errno;
 }
 
 void
diff --git a/src/modules/flow/test/float-validator.c b/src/modules/flow/test/float-validator.c
index 83a608883..63935071e 100644
--- a/src/modules/flow/test/float-validator.c
+++ b/src/modules/flow/test/float-validator.c
@@ -75,7 +75,7 @@ float_validator_open(
         }
         if (it == tail) {
             SOL_WRN("Failed to convert option 'sequence' to double %s", it);
-            errno = -EINVAL;
+            errno = EINVAL;
             goto error;
         }
         it = tail;
@@ -84,10 +84,10 @@ float_validator_open(
     return 0;
 
 no_memory:
-    errno = -ENOMEM;
+    errno = ENOMEM;
 error:
     sol_vector_clear(&mdata->values);
-    return errno;
+    return -errno;
 }
 
 int
diff --git a/src/modules/flow/test/int-generator.c b/src/modules/flow/test/int-generator.c
index 878a30b1d..33a1ae9c5 100644
--- a/src/modules/flow/test/int-generator.c
+++ b/src/modules/flow/test/int-generator.c
@@ -98,7 +98,7 @@ int_generator_open(
         }
         if (it == tail) {
             SOL_WRN("Failed to convert option 'sequence' to int %s", it);
-            errno = -EINVAL;
+            errno = EINVAL;
             goto error;
         }
         it = tail;
@@ -110,10 +110,10 @@ int_generator_open(
     return 0;
 
 no_memory:
-    errno = -ENOMEM;
+    errno = ENOMEM;
 error:
     sol_vector_clear(&mdata->values);
-    return errno;
+    return -errno;
 }
 
 void