Revert "reomoved Git module and its tests"

This reverts commit 8a66dba.

Author: tkelman

test/git.jl

@@ -0,0 +1,39 @@
+# This file is a part of Julia. License is MIT: http://julialang.org/license
+
+import Base.Git
+include("gitutils.jl")
+
+@test Git.version() >= v"1.7.3"
+
+dir = string("tmp.",randstring())
+@test !ispath(dir)
+mkdir(dir)
+@test isdir(dir)
+try cd(dir) do
+
+    run(`git init -q`)
+    run(`git config user.name "Julia Tester"`)
+    run(`git config user.email [email protected]`)
+    run(`git commit -q --allow-empty -m "initial empty commit"`)
+    git_verify(Dict(), Dict(), Dict())
+
+    # each path can have one of these content in each of head, index, work
+    # for a total of length(contents)^3 = 4^3 = 64 combinations.
+    # each path can be in any of these 64 "superpositions" before & after
+    # for a total of 64^2 = 4096 files needed to test all transitions
+    # between before and after superpositions of git repo states.
+
+    contents = [nothing, "foo", "bar", Dict{Any,Any}("baz"=>"qux")]
+    b = length(contents)
+    states = [ [ base(b,k,6) => contents[rem(div(k,b^p),b)+1] for k=0:(b^3)^2-1 ] for p=0:5 ]
+
+    git_setup(states[1:3]...)
+    try Git.transact() do
+        git_setup(states[4:6]...)
+        throw(nothing)
+    end catch x
+        is(x,nothing) || rethrow()
+    end
+    git_verify(states[1:3]...)
+
+end finally rm(dir, recursive=true) end

test/gitutils.jl

@@ -0,0 +1,114 @@
+# This file is a part of Julia. License is MIT: http://julialang.org/license
+
+function write_and_readchomp(data, cmd::Cmd)
+    r, w, p = readandwrite(cmd)
+    print(w,data); close(w)
+    v = readchomp(r)
+    wait(p)
+    return v
+end
+
+function mktree(d::Dict)
+    lstree = ""
+    for (name, data) in d
+        if isa(data, AbstractString)
+            sha1 = write_and_readchomp(data, `git hash-object -w --stdin`)
+            lstree *= "100644 blob $sha1\t$name\n"
+        elseif isa(data, Dict)
+            sha1 = mktree(data)
+            lstree *= "040000 tree $sha1\t$name\n"
+        elseif is(data, nothing)
+            # ignore it
+        else
+            error("mktree: don't know what to do with $name => $data")
+        end
+    end
+    write_and_readchomp(lstree, `git mktree`)
+end
+
+function verify_tree(d::Dict, tree::AbstractString)
+    # check that tree matches d
+    seen = Set()
+    for line in eachline(`git ls-tree $tree`)
+        m = match(r"^(\d{6}) (\w+) ([0-9a-f]{40})\t(.*)$", line)
+        @test m != nothing
+        perm, kind, sha1, name = m.captures
+        @test haskey(d,name)
+        data = d[name]
+        if isa(data, AbstractString)
+            @test kind == "blob"
+            @test data == readall(`git cat-file blob $sha1`)
+        elseif isa(data, Dict)
+            @test kind == "tree"
+            verify_tree(data, sha1)
+        else
+            error("verify_tree: don't know what to do with $name => $data")
+        end
+        push!(seen, name)
+    end
+    # check that nothing was missing from tree
+    for (name, data) in d
+        @test is(data,nothing) || in(name,seen)
+    end
+end
+
+function verify_work(d::Dict)
+    # check what's in d
+    for (name, data) in d
+        if is(data, nothing)
+            @test !ispath(name)
+            continue
+        end
+        @test ispath(name)
+        if isa(data, AbstractString)
+            @test isfile(name)
+            @test readall(name) == data
+        elseif isa(data, Dict)
+            cd(name) do
+                verify_work(data)
+            end
+        else
+            error("verify_work: don't know what to do with $name => $data")
+        end
+    end
+    # check for anything that's not in d
+    for line in eachline(`ls -A`)
+        name = chomp(line)
+        @test name == ".git" || haskey(d,name)
+    end
+end
+
+function git_verify(h::Dict, i::Dict, w::Dict)
+    verify_tree(h, "HEAD")
+    verify_tree(i, readchomp(`git write-tree`))
+    verify_work(w)
+end
+
+function git_setup(h::Dict, i::Dict, w::Dict, parents::AbstractString...)
+    # create tree objects
+    headt = mktree(h)
+    index = mktree(i)
+    work  = mktree(w)
+
+    # clear the repo
+    for line in eachline(`ls -A`)
+        name = chomp(line)
+        name == ".git" || rm(name, recursive=true)
+    end
+
+    # create the head commit
+    commit_tree = `git commit-tree $headt`
+    for parent in parents
+        commit_tree = `$commit_tree -p $parent`
+    end
+    head = write_and_readchomp(headt, commit_tree)
+    run(`git reset -q --soft $head`)
+
+    run(`git read-tree $work`)      # read work into the index
+    run(`git checkout-index -fa`)   # check the index out
+    run(`git read-tree $index`)     # setup the index
+
+    # verify that everything is as expected
+    git_verify(h, i, w)
+end
+git_setup(h::Dict, i::Dict, w::Dict) = git_setup(h, i, w, readchomp(`git rev-parse HEAD`))