From 8f502640d1d1bacf0955346a23a395825d489f6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Zemanovi=C4=8D?= <tzemanovic@gmail.com>
Date: Tue, 18 Apr 2023 09:38:10 +0100
Subject: [PATCH 1/3] make the config's `fn contextualize_config` public

---
 proptest/src/test_runner/config.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/proptest/src/test_runner/config.rs b/proptest/src/test_runner/config.rs
index 4934b1ba..04940abc 100644
--- a/proptest/src/test_runner/config.rs
+++ b/proptest/src/test_runner/config.rs
@@ -49,8 +49,10 @@ const RNG_ALGORITHM: &str = "PROPTEST_RNG_ALGORITHM";
 const DISABLE_FAILURE_PERSISTENCE: &str =
     "PROPTEST_DISABLE_FAILURE_PERSISTENCE";
 
+/// Override the config fields from environment variables, if any are set.
+/// Without the `std` feature this function returns config unchanged.
 #[cfg(feature = "std")]
-fn contextualize_config(mut result: Config) -> Config {
+pub fn contextualize_config(mut result: Config) -> Config {
     fn parse_or_warn<T: FromStr + fmt::Display>(
         src: &OsString,
         dst: &mut T,
@@ -141,8 +143,9 @@ fn contextualize_config(mut result: Config) -> Config {
     result
 }
 
+/// Without the `std` feature this function returns config unchanged.
 #[cfg(not(feature = "std"))]
-fn contextualize_config(result: Config) -> Config {
+pub fn contextualize_config(result: Config) -> Config {
     result
 }
 

From be301e6821e44ea2a72bb8ffc876a2ed2b24054b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Zemanovi=C4=8D?= <tzemanovic@gmail.com>
Date: Tue, 18 Apr 2023 09:38:41 +0100
Subject: [PATCH 2/3] contextualize the non-default config in `proptest!` macro

---
 proptest/src/sugar.rs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/proptest/src/sugar.rs b/proptest/src/sugar.rs
index 42ba5c19..e16d2dda 100644
--- a/proptest/src/sugar.rs
+++ b/proptest/src/sugar.rs
@@ -157,7 +157,7 @@ macro_rules! proptest {
         $(
             $(#[$meta])*
             fn $test_name() {
-                let mut config = $config.clone();
+                let mut config = $crate::test_runner::contextualize_config($config.clone());
                 config.test_name = Some(
                     concat!(module_path!(), "::", stringify!($test_name)));
                 $crate::proptest_helper!(@_BODY config ($($parm in $strategy),+) [] $body);
@@ -172,7 +172,7 @@ macro_rules! proptest {
         $(
             $(#[$meta])*
             fn $test_name() {
-                let mut config = $config.clone();
+                let mut config = $crate::test_runner::contextualize_config($config.clone());
                 config.test_name = Some(
                     concat!(module_path!(), "::", stringify!($test_name)));
                 $crate::proptest_helper!(@_BODY2 config ($($arg)+) [] $body);
@@ -223,25 +223,25 @@ macro_rules! proptest {
     };
 
     ($config:expr, |($($parm:pat in $strategy:expr),+ $(,)?)| $body:expr) => { {
-        let mut config = $config.__sugar_to_owned();
+        let mut config = $crate::test_runner::contextualize_config($config.__sugar_to_owned());
         $crate::sugar::force_no_fork(&mut config);
         $crate::proptest_helper!(@_BODY config ($($parm in $strategy),+) [] $body)
     } };
 
     ($config:expr, move |($($parm:pat in $strategy:expr),+ $(,)?)| $body:expr) => { {
-        let mut config = $config.__sugar_to_owned();
+        let mut config = $crate::test_runner::contextualize_config($config.__sugar_to_owned());
         $crate::sugar::force_no_fork(&mut config);
         $crate::proptest_helper!(@_BODY config ($($parm in $strategy),+) [move] $body)
     } };
 
     ($config:expr, |($($arg:tt)+)| $body:expr) => { {
-        let mut config = $config.__sugar_to_owned();
+        let mut config = $crate::test_runner::contextualize_config($config.__sugar_to_owned());
         $crate::sugar::force_no_fork(&mut config);
         $crate::proptest_helper!(@_BODY2 config ($($arg)+) [] $body);
     } };
 
     ($config:expr, move |($($arg:tt)+)| $body:expr) => { {
-        let mut config = $config.__sugar_to_owned();
+        let mut config = $crate::test_runner::contextualize_config($config.__sugar_to_owned());
         $crate::sugar::force_no_fork(&mut config);
         $crate::proptest_helper!(@_BODY2 config ($($arg)+) [move] $body);
     } };

From 22672a6230a8a018e124b5abd775491f118c7605 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Zemanovi=C4=8D?= <tzemanovic@gmail.com>
Date: Tue, 2 May 2023 08:29:54 +0200
Subject: [PATCH 3/3] changelog: add #318

---
 proptest/CHANGELOG.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/proptest/CHANGELOG.md b/proptest/CHANGELOG.md
index 0be9988c..300cf262 100644
--- a/proptest/CHANGELOG.md
+++ b/proptest/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## Unreleased
 
+### Breaking Changes
+
+- `PROPTEST_` environment variables now take precedence over tests' non-default
+  configuration.
+
 ### Bug Fixes
 
 ### New Features