ci: actually run tests on alternate compilers

Author: apoelstra

.github/workflows/rust.yml

@@ -32,6 +32,8 @@ jobs:
       - name: Checkout Toolchain
         uses: dtolnay/rust-toolchain@beta
       - name: Running test script
+        env:
+          DO_FEATURE_MATRIX: true
         run: ./contrib/test.sh
 
   Nightly:
@@ -62,6 +64,8 @@ jobs:
       - name: Checkout Toolchain
         uses: dtolnay/rust-toolchain@1.48.0
       - name: Running test script
+        env:
+          DO_FEATURE_MATRIX: true
         run: ./contrib/test.sh
 
   EmbeddedWithAlloc:

contrib/test.sh

@@ -5,9 +5,6 @@
 set -eu
 set -x
 
-# "arrayvec" feature breaks the MSRV, its added manually in DO_FEATURE_MATRIX loop below.
-FEATURES="std alloc"
-
 # Some tests require certain toolchain types.
 NIGHTLY=false
 MSRV=false