Clean up meson support for seek_stress

.github/workflows/test.sh

@@ -23,11 +23,12 @@ done
 if [ -d "./build" ]
 then
     # also pass --reconfigure since $rust_test_path, etc. may have changed
-    meson setup build $debug_opt $rust_test_path $seek_stress_test_rust_path \
-        --reconfigure 
+    meson setup build $debug_opt -Dtest_rust=true $rust_test_path \
+        $seek_stress_test_rust_path --reconfigure
 else
     # since build doesn't exist, it would be an error if we passed --reconfigure
-    meson setup build $debug_opt $rust_test_path $seek_stress_test_rust_path
+    meson setup build $debug_opt -Dtest_rust=true $rust_test_path \
+        $seek_stress_test_rust_path
 fi
 
 if [[ -z $seek_stress_test_rust_path ]]; then

tests/meson.build

@@ -145,26 +145,28 @@ if get_option('enable_tools')
     )
 endif
 
-test_rust_path = get_option('test_rust_path')
-if test_rust_path == ''
-    message('running cargo since test_rust_path is not set...')
-    if get_option('debug')
-        run_command('cargo', 'build', check: true)
-        test_rust_path = '../target/debug/dav1d'
-        seek_stress_test_rust_path  = '../target/debug/seek_stress'
-    else
-        run_command('cargo', 'build', '--release', check: true)
-        test_rust_path = '../target/release/dav1d'
-        seek_stress_test_rust_path  = '../target/release/seek_stress'
-    endif
-endif
+if get_option('test_rust')
+    test_rust_path = get_option('test_rust_path')
+    seek_stress_test_rust_path = get_option('seek_stress_test_rust_path')
 
-seek_stress_test_rust_path = get_option('seek_stress_test_rust_path')
+    if test_rust_path == '' or seek_stress_test_rust_path == ''
+        message('running cargo build since "test_rust" is set but ' +
+                '"test_rust_path" or "seek_stress_test_rust_path" isn\'t set...'
+        )
+        if get_option('debug')
+            run_command('cargo', 'build', check: true)
+            test_rust_path = '../target/debug/dav1d'
+            seek_stress_test_rust_path  = '../target/debug/seek_stress'
+        else
+            run_command('cargo', 'build', '--release', check: true)
+            test_rust_path = '../target/release/dav1d'
+            seek_stress_test_rust_path  = '../target/release/seek_stress'
+        endif
+    endif
 
-# HACK: If we're trying to test the Rust build, override the `dav1d` and
-# `seek_stress` executables to point to the versions produced by Cargo.
-# This will cause the Rust executables to be tested instead of the C versions.
-if get_option('test_rust')
+    # HACK: If we're trying to test the Rust build, override the `dav1d` and
+    # `seek_stress` executables to point to the versions produced by Cargo.
+    # This will cause the Rust executables to be tested instead of the C versions.
     dav1d = files(test_rust_path)
     seek_stress = files(seek_stress_test_rust_path)
 endif