Add diamond_deps tests for #184.

tests/diamond_deps/a/a.nimble

@@ -0,0 +1,14 @@
+# Package
+
+version       = "0.1.0"
+author        = "Dominik Picheta"
+description   = "a"
+license       = "MIT"
+
+# Dependencies
+
+requires "nim >= 0.15.3", "b", "c"
+
+
+task test, "test":
+  echo("hello")

tests/diamond_deps/b/b.nimble

@@ -0,0 +1,11 @@
+# Package
+
+version       = "0.1.0"
+author        = "Dominik Picheta"
+description   = "b"
+license       = "MIT"
+
+# Dependencies
+
+requires "nim >= 0.15.3", "d"
+

tests/diamond_deps/c/c.nimble

@@ -0,0 +1,11 @@
+# Package
+
+version       = "0.1.0"
+author        = "Dominik Picheta"
+description   = "c"
+license       = "MIT"
+
+# Dependencies
+
+requires "nim >= 0.15.3", "d"
+

tests/diamond_deps/d/d.nimble

@@ -0,0 +1,11 @@
+# Package
+
+version       = "0.1.0"
+author        = "Dominik Picheta"
+description   = "d"
+license       = "MIT"
+
+# Dependencies
+
+requires "nim >= 0.15.3"
+

tests/tester.nim

@@ -405,3 +405,18 @@ test "can dump for installed package":
     let (outp, exitCode) = execNimble("dump", "testdump")
     check: exitCode == 0
     check: outp.processOutput.inLines("desc: \"Test package for dump command\"")
+
+test "can install diamond deps (#184)":
+  cd "diamond_deps":
+    cd "d":
+      check execNimble("install", "-y").exitCode == 0
+    cd "c":
+      check execNimble("install", "-y").exitCode == 0
+    cd "b":
+      check execNimble("install", "-y").exitCode == 0
+    cd "a":
+      # TODO: This doesn't really test anything. But I couldn't quite
+      # reproduce #184.
+      let (output, exitCode) = execNimble("install", "-y")
+      checkpoint(output)
+      check exitCode == 0