Clean up plugin build workflow and docs

r2plugin/README.md

@@ -10,6 +10,9 @@ ADSP-2191) 24-bit instructions in radare2 and iaito.
 
 Requires: GCC, radare2 >= 5.8.0 (RArchPlugin API).
 
+The `Makefile` also provides `make test`, which builds the plugin and
+runs a smoke test against `../examples/isa_test.bin`.
+
 ## Usage
 
     r2 -a adsp219x -b 24 firmware.bin
@@ -20,9 +23,16 @@ Compare against the assembler-verified test ROM:
 
     r2 -a adsp219x -b 24 -q -c "pd 48" ../examples/isa_test.bin
 
+Or run the local plugin without installing it:
+
+    make test
+
 The test ROM (`isa_test.dsp`) was assembled with open21xx and
 contains known opcodes for all major instruction types.
 
+For the current verification matrix and remaining structural-only
+types, see `TESTING.md`.
+
 ## Coding Standards
 
 This plugin follows the GNU Coding Standards for C source code.