Fix the broken doctests, and add a CI job that runs the doctests

.ci/test_and_change_uuid.jl

@@ -0,0 +1,28 @@
+@static if Base.VERSION >= v"1.6"
+    using TOML
+    using Test
+else
+    using Pkg: TOML
+    using Test
+end
+
+# To generate the new UUID, we simply modify the first character of the original UUID
+const original_uuid = "ea8e919c-243c-51af-8825-aaa63cd721ce"
+const new_uuid      = "fa8e919c-243c-51af-8825-aaa63cd721ce"
+
+# `@__DIR__` is the `.ci/` folder.
+# Therefore, `dirname(@__DIR__)` is the repository root.
+const project_filename = joinpath(dirname(@__DIR__), "Project.toml")
+
+@testset "Test that the UUID is unchanged" begin
+    project_dict = TOML.parsefile(project_filename)
+    @test project_dict["uuid"] == original_uuid
+end
+
+write(
+    project_filename,
+    replace(
+        read(project_filename, String),
+        r"uuid = .*?\n" => "uuid = \"$(new_uuid)\"\n",
+    ),
+)

.github/workflows/CI.yml

@@ -40,10 +40,7 @@ jobs:
           version: ${{ matrix.julia-version }}
       # Alter the UUID so that we test this package instead of loading
       # the version that is already built into a Julia's system image.
-      - name: alter UUID
-        shell: bash
-        run: |
-          sed -i'' -e 's/ea8e919c-243c-51af-8825-aaa63cd721ce/ea8e919c-243c-51af-8825-aaa63cd721cf/' Project.toml
+      - run: julia --color=yes .ci/test_and_change_uuid.jl
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
@@ -52,3 +49,18 @@ jobs:
       - uses: codecov/codecov-action@v1
         with:
           file: lcov.info
+  doctests:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          persist-credentials: false
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: 'nightly'
+      - run: julia --color=yes .ci/test_and_change_uuid.jl
+      - run: julia --project=docs --color=yes -e 'using Pkg; Pkg.instantiate()'
+      - run: julia --project=docs --color=yes -e 'using Pkg; Pkg.develop(PackageSpec(path = pwd()))'
+      - name: Run doctests
+        run: julia --project=docs --color=yes -e 'import SHA; import Documenter; Documenter.doctest(SHA)'

docs/.gitignore

@@ -0,0 +1 @@
+Manifest.toml

docs/Project.toml

@@ -0,0 +1,5 @@
+[deps]
+Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
+
+[compat]
+Documenter = "~0.27"

docs/src/index.md

@@ -69,13 +69,7 @@ julia> digest!(ctx)
  0xa3
  0x57
  0x92
- 0x5b
- 0xc5
- 0xe1
     ⋮
- 0x19
- 0xa0
- 0x1b
  0x89
  0x4f
  0x59