Fixed a recompilation issue in CI, tweaked coverage.py a bit more

This was lost in the Travis -> GitHub transition, in serializing some of
the jobs, I missed that we need to clean between tests with different
geometry configurations. Otherwise we end up running outdated binaries,
which explains some of the weird test behavior we were seeing.

Also tweaked a few script things:
- Better subprocess error reporting (dump stderr on failure)
- Fixed a BUILDDIR rule issue in test.py
- Changed test-not-run status to None instead of undefined

.github/workflows/test.yml

@@ -13,8 +13,6 @@ jobs:
       fail-fast: false
       matrix:
         arch: [x86_64, thumb, mips, powerpc]
-    env:
-      TESTFLAGS: --coverage
 
     steps:
       - uses: actions/checkout@v2
@@ -24,6 +22,13 @@ jobs:
           sudo apt-get update -qq
           sudo apt-get install -qq python3 python3-pip lcov
           sudo pip3 install toml
+          gcc --version
+
+          # collect coverage
+          mkdir -p coverage
+          echo "TESTFLAGS=$TESTFLAGS --coverage=`
+            `coverage/${{github.job}}-${{matrix.arch}}.info" >> $GITHUB_ENV
+
       # cross-compile with ARM Thumb (32-bit, little-endian)
       - name: install-thumb
         if: matrix.arch == 'thumb'
@@ -60,7 +65,7 @@ jobs:
           echo "EXEC=qemu-ppc" >> $GITHUB_ENV
           powerpc-linux-gnu-gcc --version
           qemu-ppc -version
-      # test configurations
+
       # make sure example can at least compile
       - name: test-example
         run: |
@@ -71,45 +76,65 @@ jobs:
             -Duser_provided_block_device_erase=NULL \
             -Duser_provided_block_device_sync=NULL \
             -include stdio.h"
+
+      # test configurations
       # normal+reentrant tests
       - name: test-default
-        run: make test_dirs TESTFLAGS+="-nrk"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk"
       # NOR flash: read/prog = 1 block = 4KiB
       - name: test-nor
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_READ_SIZE=1 -DLFS_BLOCK_SIZE=4096" VERBOSE=1
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_READ_SIZE=1 -DLFS_BLOCK_SIZE=4096"
       # SD/eMMC: read/prog = 512 block = 512
       - name: test-emmc
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_READ_SIZE=512 -DLFS_BLOCK_SIZE=512"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_READ_SIZE=512 -DLFS_BLOCK_SIZE=512"
       # NAND flash: read/prog = 4KiB block = 32KiB
       - name: test-nand
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_READ_SIZE=4096 -DLFS_BLOCK_SIZE=\(32*1024\)"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_READ_SIZE=4096 -DLFS_BLOCK_SIZE=\(32*1024\)"
       # other extreme geometries that are useful for various corner cases
       - name: test-no-intrinsics
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_NO_INTRINSICS"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_NO_INTRINSICS"
       - name: test-byte-writes
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_READ_SIZE=1 -DLFS_CACHE_SIZE=1"
+        # it just takes too long to test byte-level writes when in qemu,
+        # should be plenty covered by the other configurations
+        if: matrix.arch == 'x86_64'
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_READ_SIZE=1 -DLFS_CACHE_SIZE=1"
       - name: test-block-cycles
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_BLOCK_CYCLES=1"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_BLOCK_CYCLES=1"
       - name: test-odd-block-count
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD_SIZE=256"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD_SIZE=256"
       - name: test-odd-block-size
-        run: make test TESTFLAGS+="-nrk
-          -DLFS_READ_SIZE=11 -DLFS_BLOCK_SIZE=704"
+        run: |
+          make clean
+          make test TESTFLAGS+="-nrk \
+            -DLFS_READ_SIZE=11 -DLFS_BLOCK_SIZE=704"
 
       # collect coverage
       - name: collect-coverage
         continue-on-error: true
         run: |
-          mkdir -p coverage
-          lcov $(for f in tests/*.toml.cumul.info ; do echo "-a $f" ; done) \
-            -o coverage/${{github.job}}-${{matrix.arch}}.info
           # we only care about littlefs's actual source
           lcov -e coverage/${{github.job}}-${{matrix.arch}}.info \
             $(for f in lfs*.c ; do echo "/$f" ; done) \
@@ -127,10 +152,10 @@ jobs:
         continue-on-error: true
         run: |
           mkdir -p results
-          # TODO remove the need for OBJ
+          # TODO remove the need for SRC
           make clean
           make code \
-            OBJ="$(echo lfs*.c | sed 's/\.c/\.o/g')" \
+            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \
@@ -143,7 +168,7 @@ jobs:
           mkdir -p results
           make clean
           make code \
-            OBJ="$(echo lfs*.c | sed 's/\.c/\.o/g')" \
+            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \
@@ -157,7 +182,7 @@ jobs:
           mkdir -p results
           make clean
           make code \
-            OBJ="$(echo lfs*.c | sed 's/\.c/\.o/g')" \
+            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \
@@ -171,7 +196,7 @@ jobs:
           mkdir -p results
           make clean
           make code \
-            OBJ="$(echo lfs*.c | sed 's/\.c/\.o/g')" \
+            SRC="$(echo lfs*.c)" \
             CFLAGS+=" \
               -DLFS_NO_ASSERT \
               -DLFS_NO_DEBUG \