Remove extraneous .tmp in Pkg.pin error paths

and add corresponding tests

base/pkg/entry.jl

@@ -308,9 +308,9 @@ pin(pkg::AbstractString) = pin(pkg, "")
 
 function pin(pkg::AbstractString, ver::VersionNumber)
     ispath(pkg,".git") || throw(PkgError("$pkg is not a git repo"))
-    Read.isinstalled(pkg) || throw(PkgError("$pkg cannot be pinned – not an installed package".tmp))
+    Read.isinstalled(pkg) || throw(PkgError("$pkg cannot be pinned – not an installed package"))
     avail = Read.available(pkg)
-    isempty(avail) && throw(PkgError("$pkg cannot be pinned – not a registered package".tmp))
+    isempty(avail) && throw(PkgError("$pkg cannot be pinned – not a registered package"))
     haskey(avail,ver) || throw(PkgError("$pkg – $ver is not a registered version"))
     pin(pkg, avail[ver].sha1)
 end

test/pkg.jl

@@ -59,8 +59,6 @@ temp_pkg_dir() do
     Pkg.status("Example", iob)
     str = chomp(takebuf_string(iob))
     @test endswith(str, string(Pkg.installed("Example")))
-    Pkg.rm("Example")
-    @test isempty(Pkg.installed())
 
     # adding a package with unsatisfiable julia version requirements (REPL.jl) errors
     try
@@ -95,6 +93,27 @@ temp_pkg_dir() do
         @test isa(err, PkgError)
         @test err.msg == "NonexistentPackage is not a git repo"
     end
+
+    # trying to pin a git repo under Pkg.dir that is not an installed package errors
+    try
+        Pkg.pin("METADATA", v"1.0.0")
+        error("unexpected")
+    catch err
+        @test isa(err, PkgError)
+        @test err.msg == "METADATA cannot be pinned – not an installed package"
+    end
+
+    # trying to pin an installed, registered package to an unregistered version errors
+    try
+        Pkg.pin("Example", v"2147483647.0.0")
+        error("unexpected")
+    catch err
+        @test isa(err, PkgError)
+        @test err.msg == "Example – 2147483647.0.0 is not a registered version"
+    end
+
+    Pkg.rm("Example")
+    @test isempty(Pkg.installed())
 end
 
 # testing a package with test dependencies causes them to be installed for the duration of the test
@@ -119,6 +138,15 @@ temp_pkg_dir() do
     Pkg.test("PackageWithTestDependencies")
 
     @test [keys(Pkg.installed())...] == ["PackageWithTestDependencies"]
+
+    # trying to pin an unregistered package errors
+    try
+        Pkg.pin("PackageWithTestDependencies", v"1.0.0")
+        error("unexpected")
+    catch err
+        @test isa(err, PkgError)
+        @test err.msg == "PackageWithTestDependencies cannot be pinned – not a registered package"
+    end
 end
 
 # testing a package with no runtests.jl errors