diff --git a/Makefile b/Makefile
index 31cf5bb2cd..2a3de4d18e 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ watch:
 	./node_modules/.bin/gulp watch
 
 test-only:
-	./node_modules/.bin/nyc --check-coverage --lines 85 --branches 74 --functions 85 ./node_modules/.bin/ava --verbose test/
+	./node_modules/.bin/nyc --check-coverage --lines 85 --branches 74 --functions 85 ./node_modules/.bin/ava --verbose --concurrency 5 test/
 	./node_modules/.bin/nyc report --reporter=lcov
 
 lint:
diff --git a/src/cli/commands/install.js b/src/cli/commands/install.js
index 11f7549668..b6fa0e16e9 100644
--- a/src/cli/commands/install.js
+++ b/src/cli/commands/install.js
@@ -12,7 +12,6 @@
 import type { RegistryNames } from "../../registries/index.js";
 import type { Reporter } from "kreporters";
 import type Config from "../../config.js";
-import type { DependencyRequestPatterns } from "../../types.js";
 import Lockfile from "../../lockfile/index.js";
 import lockStringify from "../../lockfile/stringify.js";
 import PackageInstallScripts from "../../package-install-scripts.js";
@@ -31,18 +30,6 @@ let invariant = require("invariant");
 let emoji     = require("node-emoji");
 let path      = require("path");
 
-type FetchResolveParams = {
-  totalSteps: number,
-  patterns: Array<string>,
-  requests: DependencyRequestPatterns
-};
-
-type FetchResolveReturn = {
-  patterns: Array<string>,
-  total: number,
-  step: number
-};
-
 type InstallActions = "install" | "update" | "uninstall";
 
 export class Install {
diff --git a/src/package-linker.js b/src/package-linker.js
index 680cfc6db5..6d0a5ed764 100644
--- a/src/package-linker.js
+++ b/src/package-linker.js
@@ -223,6 +223,10 @@ export default class PackageLinker {
 
   async copyModules(patterns: Array<string>): Promise<void> {
     let flatTree = await this.initCopyModules(patterns);
+    // sorted tree makes file creation and copying not to interfere with each other
+    flatTree = flatTree.sort((dep1, dep2) => {
+      return dep1[0].localeCompare(dep2[0]);
+    });
     let self = this;
 
     //
diff --git a/test/commands/install.js b/test/commands/install.js
index 79d5707e48..35adb3588c 100755
--- a/test/commands/install.js
+++ b/test/commands/install.js
@@ -75,6 +75,11 @@ async function run(flags, args, name, checkInstalled, beforeInstall) {
   await clean(cwd, removeLock);
 }
 
+async function getPackageVersion(config, packagePath) {
+  return JSON.parse(await fs.readFile(
+    path.join(config.cwd, `node_modules/${packagePath}/package.json`))).version;
+}
+
 test("root install from shrinkwrap", () => {
   return run({}, [], "root-install-with-lockfile");
 });
@@ -155,13 +160,8 @@ test("install should dedupe dependencies avoiding conflicts 0", () => {
   // B@1.0.0
   // should result in B@2.0.0 not flattened
   return run({}, [], "install-should-dedupe-avoiding-conflicts-0", async (config) => {
-    let rawDepBPackage = await fs.readFile(path.join(config.cwd, "node_modules/dep-b/package.json"));
-    assert.equal(JSON.parse(rawDepBPackage).version, "1.0.0");
-
-    rawDepBPackage = await fs.readFile(
-      path.join(config.cwd, "node_modules/dep-a/node_modules/dep-b/package.json")
-    );
-    assert.equal(JSON.parse(rawDepBPackage).version, "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-b"), "2.0.0");
   });
 });
 
@@ -169,11 +169,8 @@ test("install should dedupe dependencies avoiding conflicts 1", () => {
   // A@2.0.1 -> B@2.0.0
   // should result in B@2.0.0 flattened
   return run({}, [], "install-should-dedupe-avoiding-conflicts-1", async (config) => {
-    let rawDepBPackage = await fs.readFile(path.join(config.cwd, "node_modules/dep-b/package.json"));
-    assert.equal(JSON.parse(rawDepBPackage).version, "2.0.0");
-
-    rawDepBPackage = await fs.readFile(path.join(config.cwd, "node_modules/dep-a/package.json"));
-    assert.equal(JSON.parse(rawDepBPackage).version, "2.0.1");
+    assert.equal(await getPackageVersion(config, "dep-b"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "2.0.1");
   });
 });
 
@@ -188,18 +185,12 @@ test("install should dedupe dependencies avoiding conflicts 2", () => {
   // C@2
 
   return run({}, [], "install-should-dedupe-avoiding-conflicts-2", async (config) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/node_modules/dep-b/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-c/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-d/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/node_modules/dep-c/package.json"))).version, "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-b"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b/node_modules/dep-c"), "1.0.0");
   });
 });
 
@@ -213,16 +204,11 @@ test("install should dedupe dependencies avoiding conflicts 3", () => {
   // C@2
   // D@1
   return run({}, [], "install-should-dedupe-avoiding-conflicts-3", async (config) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-c/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-d/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/node_modules/dep-c/package.json"))).version, "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-c"), "1.0.0");
   });
 });
 
@@ -238,16 +224,11 @@ test("install should dedupe dependencies avoiding conflicts 4", () => {
   // B@2
   // D@1
   return run({}, [], "install-should-dedupe-avoiding-conflicts-4", async (config) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-c/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-d/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/node_modules/dep-c/package.json"))).version, "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-c"), "1.0.0");
   });
 });
 
@@ -264,18 +245,75 @@ test("install should dedupe dependencies avoiding conflicts 5", () => {
   //     -> B@2
 
   return run({}, [], "install-should-dedupe-avoiding-conflicts-5", async (config) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-c/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-d/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-d/node_modules/dep-a/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-d/node_modules/dep-b/package.json"))).version, "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d/node_modules/dep-a"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d/node_modules/dep-b"), "2.0.0");
+
+  });
+});
+
+test("install should dedupe dependencies avoiding conflicts 6 (jest/jest-runtime case)", () => {
+  // C@1 -> D@1 -> E@1
+  // B@1 -> C@1 -> D@1 -> E@1
+  // D@2
+  // E@2
+
+  // should become
+
+  // C@1 -> D@1
+  //     -> E@1
+  // B@1
+  // D@2
+  // E@2
+
+  return run({}, [], "install-should-dedupe-avoiding-conflicts-6", async (config) => {
+    assert.equal(await getPackageVersion(config, "dep-b"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-e"), "2.0.0");
+
+    assert.equal(await getPackageVersion(config, "dep-c/node_modules/dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c/node_modules/dep-e"), "1.0.0");
+  });
+});
+
+test("install should dedupe dependencies avoiding conflicts 7", () => {
+  // A@1 -> C@1 -> D@1 -> E@1
+  // B@1 -> C@1 -> D@1 -> E@1
+  // C@2
+  // D@2
+  // E@2
+
+  // should become
+
+  // A@1 -> C@1
+  //     -> D@1
+  //     -> E@1
+  // B@1 -> C@1
+  //     -> D@1
+  //     -> E@1
+  // C@2
+  // D@2
+  // E@2
+
+  return run({}, [], "install-should-dedupe-avoiding-conflicts-7", async (config) => {
+    assert.equal(await getPackageVersion(config, "dep-a"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-c"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-d"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-e"), "2.0.0");
+
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-c"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-e"), "1.0.0");
+
+
+    assert.equal(await getPackageVersion(config, "dep-b/node_modules/dep-c"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b/node_modules/dep-d"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b/node_modules/dep-e"), "1.0.0");
 
   });
 });
@@ -294,7 +332,7 @@ test("upgrade scenario", () => {
 
   return run({ save: true }, ["left-pad@0.0.9"], "install-upgrade-scenario", async (config) => {
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/left-pad/package.json"))).version,
+      await getPackageVersion(config, "left-pad"),
       "0.0.9"
     );
     assert.deepEqual(
@@ -314,7 +352,7 @@ test("upgrade scenario", () => {
 
     return run({save: true}, ["left-pad@1.1.0"], "install-upgrade-scenario", async (config) => {
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/left-pad/package.json"))).version,
+        await getPackageVersion(config, "left-pad"),
         "1.1.0"
       );
       assert.deepEqual(
@@ -349,21 +387,21 @@ test("upgrade scenario 2 (with sub dependencies)", async () => {
 
   return run({}, [], fixture, async (config) => {
     assert(semver.satisfies(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+      await getPackageVersion(config, "mime-db"),
       "~1.0.1")
     );
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+      await getPackageVersion(config, "mime-types"),
       "2.0.0"
     );
 
     return run({save: true}, ["mime-types@2.1.11"], fixture, async (config) => {
       assert(semver.satisfies(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+        await getPackageVersion(config, "mime-db"),
         "~1.23.0"
       ));
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+        await getPackageVersion(config, "mime-types"),
         "2.1.11"
       );
 
@@ -397,7 +435,7 @@ test("downgrade scenario", () => {
 
   return run({save: true}, ["left-pad@1.1.0"], "install-downgrade-scenario", async (config) => {
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/left-pad/package.json"))).version,
+      await getPackageVersion(config, "left-pad"),
       "1.1.0"
     );
     assert.deepEqual(
@@ -418,7 +456,7 @@ test("downgrade scenario", () => {
 
     return run({save: true}, ["left-pad@0.0.9"], "install-downgrade-scenario", async (config) => {
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/left-pad/package.json"))).version,
+        await getPackageVersion(config, "left-pad"),
         "0.0.9"
       );
       assert.deepEqual(
@@ -463,12 +501,9 @@ test("install have a clean node_modules after lockfile update (branch switch sce
   await fs.copy(path.join(cwd, "package.json.before"), path.join(cwd, "package.json"));
 
   return run({}, [], fixture, async (config) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/package.json"))).version, "2.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/node_modules/dep-b/package.json"))).version, "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "2.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a/node_modules/dep-b"), "1.0.0");
 
     await fs.unlink(path.join(config.cwd, "fbkpm.lock"));
     await fs.unlink(path.join(config.cwd, "package.json"));
@@ -477,10 +512,8 @@ test("install have a clean node_modules after lockfile update (branch switch sce
     await fs.copy(path.join(cwd, "package.json.after"), path.join(cwd, "package.json"));
 
     return run({}, [], fixture, async (config) => {
-      assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-        "node_modules/dep-a/package.json"))).version, "1.2.0");
-      assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-        "node_modules/dep-b/package.json"))).version, "1.2.0");
+      assert.equal(await getPackageVersion(config, "dep-a"), "1.2.0");
+      assert.equal(await getPackageVersion(config, "dep-b"), "1.2.0");
 
       await fs.unlink(path.join(config.cwd, "fbkpm.lock"));
       await fs.unlink(path.join(config.cwd, "package.json"));
@@ -503,10 +536,8 @@ test("install have a clean node_modules after lockfile update (branch switch sce
   await fs.copy(path.join(cwd, "package.json.before"), path.join(cwd, "package.json"));
 
   return run({}, [], fixture, async (config) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-a/package.json"))).version, "1.0.0");
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/dep-b/package.json"))).version, "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-a"), "1.0.0");
+    assert.equal(await getPackageVersion(config, "dep-b"), "1.0.0");
 
     await fs.unlink(path.join(config.cwd, "fbkpm.lock"));
     await fs.unlink(path.join(config.cwd, "package.json"));
@@ -515,8 +546,7 @@ test("install have a clean node_modules after lockfile update (branch switch sce
     await fs.copy(path.join(cwd, "package.json.after"), path.join(cwd, "package.json"));
 
     return run({}, [], fixture, async (config) => {
-      assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-        "node_modules/dep-a/package.json"))).version, "1.2.0");
+      assert.equal(await getPackageVersion(config, "dep-a"), "1.2.0");
 
       assert(!await fs.exists(path.join(config.cwd, "node_modules/dep-b")));
 
@@ -531,7 +561,7 @@ test("uninstall should remove dependency from package.json, fbkpm.lock and node_
 
   return run({}, [], "uninstall-should-clean", async (config, reporter) => {
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/dep-a/package.json"))).version,
+      await getPackageVersion(config, "dep-a"),
       "1.0.0"
     );
 
@@ -573,15 +603,15 @@ test("uninstall should remove subdependencies", () => {
 
   return run({}, [], "uninstall-should-remove-subdependencies", async (config, reporter) => {
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/dep-a/package.json"))).version,
+      await getPackageVersion(config, "dep-a"),
       "1.0.0"
     );
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/dep-b/package.json"))).version,
+      await getPackageVersion(config, "dep-b"),
       "1.0.0"
     );
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/dep-c/package.json"))).version,
+      await getPackageVersion(config, "dep-c"),
       "1.0.0"
     );
 
@@ -624,13 +654,10 @@ test.skip("install --save should add missing deps to fbkpm and mirror (PR import
   let cwd = path.join(fixturesLoc, fixture);
   await fs.copy(path.join(cwd, "fbkpm.lock.before"), path.join(cwd, "fbkpm.lock"));
 
-  return run({save: true}, [], fixture, async (config, reporter) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/mime-types/package.json"))).version, "2.0.0");
-    assert(semver.satisfies(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/mime-db/package.json"))).version, "~1.0.1"));
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/fake-fbkpm-dependency/package.json"))).version, "1.0.1");
+  return run({save: true}, [], fixture, async (config) => {
+    assert.equal(await getPackageVersion(config, "mime-types"), "2.0.0");
+    assert(semver.satisfies(await getPackageVersion(config, "mime-db"), "~1.0.1"));
+    assert.equal(await getPackageVersion(config, "fake-fbkpm-dependency"), "1.0.1");
 
     let mirror = await fs.walk(path.join(config.cwd, mirrorPath));
     assert.equal(mirror.length, 3);
@@ -652,7 +679,8 @@ test.skip("install --save should add missing deps to fbkpm and mirror (PR import
 });
 
 // TODO https://github.com/facebook/fbkpm/issues/78
-test.skip("install --save should update a dependency to fbkpm and mirror (PR import scenario 2)", async () => {
+test.skip("install --save should update a dependency to fbkpm and mirror (PR import scenario 2)",
+async () => {
   // mime-types@2.0.0 is saved in local mirror and gets updated to mime-types@2.1.11 via
   // a change in package.json,
   // files in mirror, fbkpm.lock, package.json and node_modules should reflect that
@@ -665,11 +693,11 @@ test.skip("install --save should update a dependency to fbkpm and mirror (PR imp
 
   return run({}, [], fixture, async (config) => {
     assert(semver.satisfies(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+      await getPackageVersion(config, "mime-db"),
       "~1.0.1")
     );
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+      await getPackageVersion(config, "mime-types"),
       "2.0.0"
     );
 
@@ -678,11 +706,11 @@ test.skip("install --save should update a dependency to fbkpm and mirror (PR imp
 
     return run({save: true}, [], fixture, async (config) => {
       assert(semver.satisfies(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+        await getPackageVersion(config, "mime-db"),
         "~1.23.0"
       ));
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+        await getPackageVersion(config, "mime-types"),
         "2.1.11"
       );
 
@@ -715,11 +743,9 @@ test("install --initMirror should add init mirror deps from package.json", async
   let fixture = "install-init-mirror";
 
   // initMirror gets converted to save flag in cli/install.js
-  return run({save: true}, [], fixture, async (config, reporter) => {
-    assert.equal(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/mime-types/package.json"))).version, "2.0.0");
-    assert(semver.satisfies(JSON.parse(await fs.readFile(path.join(config.cwd,
-      "node_modules/mime-db/package.json"))).version, "~1.0.1"));
+  return run({save: true}, [], fixture, async (config) => {
+    assert.equal(await getPackageVersion(config, "mime-types"), "2.0.0");
+    assert(semver.satisfies(await getPackageVersion(config, "mime-db"), "~1.0.1"));
 
     let mirror = await fs.walk(path.join(config.cwd, mirrorPath));
     assert.equal(mirror.length, 2);
@@ -750,26 +776,25 @@ test("install --save with new dependency should be deterministic", async () => {
 
   return run({}, [], fixture, async (config) => {
     assert(semver.satisfies(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+      await getPackageVersion(config, "mime-db"),
       "~1.0.1")
     );
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+      await getPackageVersion(config, "mime-types"),
       "2.0.0"
     );
 
     return run({save: true}, ["mime-db@1.23.0"], fixture, async (config) => {
       assert(semver.satisfies(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+        await getPackageVersion(config, "mime-db"),
         "~1.23.0"
       ));
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+        await getPackageVersion(config, "mime-types"),
         "2.0.0"
       );
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd,
-          "node_modules/mime-types/node_modules/mime-db/package.json"))).version,
+        await getPackageVersion(config, "mime-types/node_modules/mime-db"),
         "1.0.3"
       );
       assert.deepEqual(
@@ -808,21 +833,21 @@ test.skip("install --save with new dependency should be deterministic 2", async
 
   return run({}, [], fixture, async (config) => {
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+      await getPackageVersion(config, "mime-db"),
       "1.0.1"
     );
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+      await getPackageVersion(config, "mime-types"),
       "2.0.0"
     );
 
     return run({save: true}, ["mime-db@1.0.3"], fixture, async (config) => {
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-db/package.json"))).version,
+        await getPackageVersion(config, "mime-db"),
         "1.0.3"
       );
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/mime-types/package.json"))).version,
+        await getPackageVersion(config, "mime-types"),
         "2.0.0"
       );
       assert(!await fs.exists(path.join(config.cwd, "node_modules/mime-types/node-modules/mime-db")));
@@ -849,7 +874,6 @@ test.skip("install --save with new dependency should be deterministic 2", async
   });
 });
 
-
 test("install --save should ignore cache", () => {
   // left-pad@1.1.0 gets installed without --save
   // left-pad@1.1.0 gets installed with --save
@@ -860,13 +884,13 @@ test("install --save should ignore cache", () => {
   let fixture = "install-save-to-mirror-when-cached";
   return run({}, ["left-pad@1.1.0"], fixture, async (config) => {
     assert.equal(
-      JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/left-pad/package.json"))).version,
+      await getPackageVersion(config, "left-pad"),
       "1.1.0"
     );
 
     return run({save: true}, ["left-pad@1.1.0"], fixture, async (config) => {
       assert.equal(
-        JSON.parse(await fs.readFile(path.join(config.cwd, "node_modules/left-pad/package.json"))).version,
+        await getPackageVersion(config, "left-pad"),
         "1.1.0"
       );
       assert.deepEqual(
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/.npmrc b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/.npmrc
new file mode 100644
index 0000000000..d912bd785c
--- /dev/null
+++ b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/.npmrc
@@ -0,0 +1 @@
+kpm-offline-mirror=./mirror-for-offline
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/fbkpm.lock b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/fbkpm.lock
new file mode 100644
index 0000000000..72c72ffe65
--- /dev/null
+++ b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/fbkpm.lock
@@ -0,0 +1,30 @@
+dep-b@1.0.0:
+  name dep-b
+  version "1.0.0"
+  resolved dep-b-1.0.0.tgz#3ec41d539ec81cbb0b00f3f77cee143104153783
+  dependencies:
+    dep-c "1.0.0"
+dep-c@1.0.0:
+  name dep-c
+  version "1.0.0"
+  resolved dep-c-1.0.0.tgz#43df1196c1b62b89ed7169b6b93493d8420763b6
+  dependencies:
+    dep-d "1.0.0"
+dep-d@1.0.0:
+  name dep-d
+  version "1.0.0"
+  resolved dep-d-1.0.0.tgz#175ce924c6413b1feeb68b976ae769260cfe0d86
+  dependencies:
+    dep-e "1.0.0"
+dep-d@2.0.0:
+  name dep-d
+  version "2.0.0"
+  resolved dep-d-2.0.0.tgz#ada909b78f52d88a60e9c8583ddc0310ff16da40
+dep-e@1.0.0:
+  name dep-e
+  version "1.0.0"
+  resolved dep-e-1.0.0.tgz#8baa9f7eda12e71a95ccfce7e31ace5867617014
+dep-e@2.0.0:
+  name dep-e
+  version "2.0.0"
+  resolved dep-e-2.0.0.tgz#c326a657226d79e68a2208f62a3f3f9f657416a9
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-b-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-b-1.0.0.tgz
new file mode 100644
index 0000000000..73deff4159
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-c-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-c-1.0.0.tgz
new file mode 100644
index 0000000000..7110975d3a
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-d-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-d-1.0.0.tgz
new file mode 100644
index 0000000000..7aa4321402
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-d-2.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-d-2.0.0.tgz
new file mode 100644
index 0000000000..2135e2fd15
Binary files /dev/null and b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-d-2.0.0.tgz differ
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-e-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-e-1.0.0.tgz
new file mode 100644
index 0000000000..ca6c2e109a
Binary files /dev/null and b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-e-1.0.0.tgz differ
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-e-2.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-e-2.0.0.tgz
new file mode 100644
index 0000000000..853b66c35b
Binary files /dev/null and b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/mirror-for-offline/dep-e-2.0.0.tgz differ
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/package.json b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/package.json
new file mode 100644
index 0000000000..66bedd2b7d
--- /dev/null
+++ b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-6/package.json
@@ -0,0 +1,8 @@
+{
+  "dependencies": {
+    "dep-b": "1.0.0",
+    "dep-c": "1.0.0",
+    "dep-d": "2.0.0",
+    "dep-e": "2.0.0"
+  }
+}
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/.npmrc b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/.npmrc
new file mode 100644
index 0000000000..d912bd785c
--- /dev/null
+++ b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/.npmrc
@@ -0,0 +1 @@
+kpm-offline-mirror=./mirror-for-offline
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/fbkpm.lock b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/fbkpm.lock
new file mode 100644
index 0000000000..66aa3cc232
--- /dev/null
+++ b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/fbkpm.lock
@@ -0,0 +1,40 @@
+dep-a@1.0.0:
+  name dep-a
+  version "1.0.0"
+  resolved dep-a-1.0.0.tgz#e7f20878f3696af17ef69934c320885ffab98651
+  dependencies:
+    dep-c "1.0.0"
+dep-b@1.0.0:
+  name dep-b
+  version "1.0.0"
+  resolved dep-b-1.0.0.tgz#3ec41d539ec81cbb0b00f3f77cee143104153783
+  dependencies:
+    dep-c "1.0.0"
+dep-c@1.0.0:
+  name dep-c
+  version "1.0.0"
+  resolved dep-c-1.0.0.tgz#43df1196c1b62b89ed7169b6b93493d8420763b6
+  dependencies:
+    dep-d "1.0.0"
+dep-c@2.0.0:
+  name dep-c
+  version "2.0.0"
+  resolved dep-c-2.0.0.tgz#be95e9930b466ac728ba44f63b9888aa5c7a78b8
+dep-d@1.0.0:
+  name dep-d
+  version "1.0.0"
+  resolved dep-d-1.0.0.tgz#175ce924c6413b1feeb68b976ae769260cfe0d86
+  dependencies:
+    dep-e "1.0.0"
+dep-d@2.0.0:
+  name dep-d
+  version "2.0.0"
+  resolved dep-d-2.0.0.tgz#ada909b78f52d88a60e9c8583ddc0310ff16da40
+dep-e@1.0.0:
+  name dep-e
+  version "1.0.0"
+  resolved dep-e-1.0.0.tgz#8baa9f7eda12e71a95ccfce7e31ace5867617014
+dep-e@2.0.0:
+  name dep-e
+  version "2.0.0"
+  resolved dep-e-2.0.0.tgz#c326a657226d79e68a2208f62a3f3f9f657416a9
diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-a-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-a-1.0.0.tgz
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-c-2.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-c-2.0.0.tgz
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-d-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-d-1.0.0.tgz
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-e-1.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-e-1.0.0.tgz
new file mode 100644
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-e-2.0.0.tgz b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/mirror-for-offline/dep-e-2.0.0.tgz
new file mode 100644
index 0000000000..853b66c35b
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diff --git a/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/package.json b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/package.json
new file mode 100644
index 0000000000..07a737fdab
--- /dev/null
+++ b/test/fixtures/install/install-should-dedupe-avoiding-conflicts-7/package.json
@@ -0,0 +1,9 @@
+{
+  "dependencies": {
+    "dep-a": "1.0.0",
+    "dep-b": "1.0.0",
+    "dep-c": "2.0.0",
+    "dep-d": "2.0.0",
+    "dep-e": "2.0.0"
+  }
+}