diff --git a/scenarios/fork/requires-python-full-prerelease.toml b/scenarios/fork/requires-python-full-prerelease.toml
index 2cf49af0..0a7c267d 100644
--- a/scenarios/fork/requires-python-full-prerelease.toml
+++ b/scenarios/fork/requires-python-full-prerelease.toml
@@ -13,6 +13,9 @@ universal = true
 [expected]
 satisfiable = false
 
+[environment]
+python = "3.12"
+
 [root]
 requires_python = ">=3.10"
 requires = [
diff --git a/scenarios/fork/requires-python-full.toml b/scenarios/fork/requires-python-full.toml
index 1b104a6d..43aefd7d 100644
--- a/scenarios/fork/requires-python-full.toml
+++ b/scenarios/fork/requires-python-full.toml
@@ -13,6 +13,9 @@ universal = true
 [expected]
 satisfiable = false
 
+[environment]
+python = "3.12"
+
 [root]
 requires_python = ">=3.10"
 requires = [
diff --git a/scenarios/fork/requires-python.toml b/scenarios/fork/requires-python.toml
index 6ed03e9a..b0ad4dcc 100644
--- a/scenarios/fork/requires-python.toml
+++ b/scenarios/fork/requires-python.toml
@@ -10,6 +10,9 @@ universal = true
 [expected]
 satisfiable = false
 
+[environment]
+python = "3.12"
+
 [root]
 requires_python = ">=3.10"
 requires = [