test: added scripts for measuring the test coverage

utils/test-coverage/0_cleanup.sh

@@ -0,0 +1,4 @@
+#! /bin/sh
+
+rm noir_tests.profdata `find . -name "*.profraw"`
+cargo clean

utils/test-coverage/1_test.sh

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+#! /bin/sh
+
+set -e
+
+export RUSTFLAGS="-C instrument-coverage"
+cargo test

utils/test-coverage/2_profdata.sh

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+#! /bin/sh
+
+llvm-profdata merge -sparse `find . -name "*.profraw"` -o noir_tests.profdata

utils/test-coverage/3_cov.sh

@@ -0,0 +1,3 @@
+#! /bin/sh
+
+llvm-cov show -Xdemangler=rustfilt target/debug/nargo -instr-profile=noir_tests.profdata -show-line-counts-or-regions -show-instantiations

utils/test-coverage/README.txt

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+This directory includes scripts that help measure the test coverage of Noir.
+
+They should be run from the main directory of the repo like this:
+
+utils/test-coverage/0_cleanup.sh
+utils/test-coverage/1_test.sh
+...
+etc.
+
+Short description of what each of these scripts does:
+
+0_cleanup.sh:
+  Cleans up the files from a previous test coverage measurement.
+
+1_test.sh:
+  Runs the testsuite with test coverage measurement enabled. Testsuite run is
+  about 8 times slower than normal. Produces lots of *.profraw files all over
+  the place. A typical test run produced: 6,966,994 KiB in 1331 files
+
+2_profdata.sh:
+  Combines all the *.profraw files into a single file, called
+  'noir_tests.profdata'.
+
+3_cov.sh:
+  Produces a test coverage report. What the test does is just an example. You
+  can use the command, called by the script and modify its parameters, to
+  produce all kinds of reports. For specific details, you should consult the
+  documentation for the llvm-cov command.