pw_fuzzer: Reenable fuzzer unit tests

This CL reenables the unit tests generated from fuzzers by non-fuzzing
toolchains. It also adds a `enable_test_if` parameter to `pw_fuzzer` to
allow setting the `enable_if` parameter on the generated test. This flag
is used to disable the tests that have bit-rotted. They will be fixed in
subsequent CLs.

Change-Id: I66794d02a99a5f279358f2f3f334bb60bafd2824
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/131590
Reviewed-by: Alexei Frolov <frolv@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
Commit-Queue: Aaron Green <aarongreen@google.com>

6 files changed, 23 insertions, 7 deletions

diff --git a/pw_bluetooth_hci/BUILD.gn b/pw_bluetooth_hci/BUILD.gn
index 0f5107163..45cd1b78c 100644
--- a/pw_bluetooth_hci/BUILD.gn
+++ b/pw_bluetooth_hci/BUILD.gn
@@ -100,6 +100,7 @@ pw_fuzzer("uart_transport_fuzzer") {
     dir_pw_status,
     dir_pw_stream,
   ]
+  enable_test_if = false
 }
 
 pw_doc_group("docs") {
diff --git a/pw_fuzzer/BUILD.gn b/pw_fuzzer/BUILD.gn
index 0c47c0fe9..c53650ba6 100644
--- a/pw_fuzzer/BUILD.gn
+++ b/pw_fuzzer/BUILD.gn
@@ -92,6 +92,7 @@ pw_fuzzer("toy_fuzzer") {
     dir_pw_span,
     dir_pw_string,
   ]
+  enable_test_if = false
 }
 
 pw_test_group("tests") {
diff --git a/pw_fuzzer/docs.rst b/pw_fuzzer/docs.rst
index db456c021..02bf05f45 100644
--- a/pw_fuzzer/docs.rst
+++ b/pw_fuzzer/docs.rst
@@ -68,7 +68,9 @@ Building fuzzers with GN
 
 To build a fuzzer, do the following:
 
-1. Add the GN target to the module using ``pw_fuzzer`` GN template.
+1. Add the GN target to the module using ``pw_fuzzer`` GN template. If you wish
+   to limit when the generated unit test is run, you can set `enable_test_if` in
+   the same manner as `enable_if` for `pw_test`:
 
 .. code::
 
@@ -78,10 +80,12 @@ To build a fuzzer, do the following:
   pw_fuzzer("my_fuzzer") {
     sources = [ "my_fuzzer.cc" ]
     deps = [ ":my_lib" ]
+    enable_test_if = device_has_1m_flash
   }
 
-2. Add the generated unit test to the module's test group. This helps verify the
-   fuzzer can build and run, even when not being built in a fuzzing toolchain.
+2. Add the generated unit test to the module's test group. This test verifies
+   the fuzzer can build and run, even when not being built in a fuzzing
+   toolchain.
 
 .. code::
 
diff --git a/pw_fuzzer/fuzzer.gni b/pw_fuzzer/fuzzer.gni
index bf47e8695..a43a2d9cb 100644
--- a/pw_fuzzer/fuzzer.gni
+++ b/pw_fuzzer/fuzzer.gni
@@ -31,6 +31,10 @@ import("$dir_pw_unit_test/test.gni")
 # for verifying the fuzz target function compiles, links, and runs even when not
 # using a fuzzing-capable host or toolchain.
 #
+# Args:
+#   - enable_test_if: (optional) Passed as `enable_if` to the unit test.
+#   Remaining arguments are the same as `pw_executable`.
+#
 template("pw_fuzzer") {
   if (!pw_toolchain_FUZZING_ENABLED) {
     pw_error(target_name) {
@@ -46,7 +50,12 @@ template("pw_fuzzer") {
     pw_executable(target_name) {
       configs = []
       deps = []
-      forward_variables_from(invoker, "*", [ "visibility" ])
+      forward_variables_from(invoker,
+                             "*",
+                             [
+                               "enable_test_if",
+                               "visibility",
+                             ])
       forward_variables_from(invoker, [ "visibility" ])
       configs += [ "$dir_pw_fuzzer:engine" ]
       deps += [ dir_pw_fuzzer ]
@@ -54,12 +63,10 @@ template("pw_fuzzer") {
   }
 
   pw_test("${target_name}_test") {
-    # TODO(b/234891784): Re-enable when there's better configurability for
-    # on-device fuzz testing.
-    enable_if = false
     deps = []
     forward_variables_from(invoker, "*", [ "visibility" ])
     forward_variables_from(invoker, [ "visibility" ])
     deps += [ "$dir_pw_fuzzer:run_as_unit_test" ]
+    enable_if = !defined(enable_test_if) || enable_test_if
   }
 }
diff --git a/pw_protobuf/BUILD.gn b/pw_protobuf/BUILD.gn
index 267b999eb..0e0dd3b50 100644
--- a/pw_protobuf/BUILD.gn
+++ b/pw_protobuf/BUILD.gn
@@ -265,6 +265,7 @@ pw_fuzzer("encoder_fuzzer") {
     "fuzz.h",
   ]
   deps = [ ":pw_protobuf" ]
+  enable_test_if = false
 }
 
 pw_fuzzer("decoder_fuzzer") {
@@ -273,4 +274,5 @@ pw_fuzzer("decoder_fuzzer") {
     "fuzz.h",
   ]
   deps = [ ":pw_protobuf" ]
+  enable_test_if = false
 }
diff --git a/pw_tokenizer/BUILD.gn b/pw_tokenizer/BUILD.gn
index d114ed293..fc276f456 100644
--- a/pw_tokenizer/BUILD.gn
+++ b/pw_tokenizer/BUILD.gn
@@ -280,6 +280,7 @@ pw_fuzzer("token_database_fuzzer") {
     "$dir_pw_preprocessor",
     dir_pw_span,
   ]
+  enable_test_if = false
 }
 
 pw_fuzzer("detokenize_fuzzer") {